Communications method and apparatus for determining a random access association period

ABSTRACT

This application discloses a communications method and apparatus. The method includes: obtaining, by a terminal device, downlink synchronization signal block index information; receiving, by the terminal device, information used to indicate an association relationship between a random access resource RO and a synchronization signal block; and accessing, by the terminal device, a network device based on the information on an RO corresponding to the synchronization signal block index information. This application further discloses a corresponding apparatus. A time-frequency location of a random access resource associated with each downlink synchronization signal is indicated, so that the terminal device obtains, through downlink synchronization, a time-frequency location for sending an uplink random access signal, to avoid a blind attempt of the terminal device and a beam mismatch of the network device occurring when the network device receives a random access signal, thereby improving efficiency.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2019/071634, filed on Jan. 14, 2019, which claims priority ofChinese Patent Application No. 201810032285.5, filed on Jan. 12, 2018.The disclosures of the aforementioned applications are herebyincorporated herein by reference in their entireties.

TECHNICAL FIELD

This application relates to the field of communications technologies,and in particular, to a communications method and apparatus.

BACKGROUND

Before communicating with a terminal device, a base station first needsto perform uplink and downlink synchronization. During the downlinksynchronization, the base station sends downlink synchronization signalsby using a plurality of transmit beams. The terminal device receives anddetects the downlink synchronization signals by using one or morereceive beams, to obtain an optimal downlink transmit and receive beampair, time information, and system information. The uplinksynchronization is completed with help of a random access process. Theterminal device first sends a random access signal. The base stationdetects the random access signal to obtain an optimal uplink transmitand receive beam pair, an uplink time, and the like, and to finallyimplement the uplink synchronization between the base station and theterminal device.

In a New Radio (NR) communications system, different random accessresources may be in association relationships with different beams, or abase station uses different beams to receive uplink signals on differentrandom access resources. Therefore, different beams of the base stationmay have different base station coverage areas. Terminal devices senduplink signals or receive downlink signals in different areas. Theuplink signals received by the base station or the downlink signalsreceived by the terminal devices have different demodulation ordetection performance. As shown in FIG. 1, when a terminal device sendsan uplink signal in a beam direction aligned with an area in which theterminal device is located, a signal received by the base station hasbest demodulation or detection performance; or when a terminal devicesends an uplink signal in a beam direction non-aligned with an area inwhich the terminal device is located, a signal received by the basestation has relatively poor demodulation or detection performance.Therefore, when implementing the uplink synchronization between the basestation and the terminal device, the terminal device needs to select asuitable or an optimal base station receive beam to send an uplinksignal or an optimal base station transmit beam receive a downlinksignal in the random access process.

When the terminal device performs an initial access process, theterminal device first obtains beam information from a downlinksynchronization signal block. Therefore, the downlink synchronizationsignal block should be in an association relationship with a randomaccess resource. However, no solution for associating a downlinksynchronization signal block with a random access resource is provided.

SUMMARY

This application provides a communications method and apparatus, toresolve a problem about how to associate a downlink synchronizationsignal block with a random access resource.

According to an aspect of this application, a communications method isprovided, including: obtaining, by a terminal device, downlinksynchronization signal block index information; receiving, by theterminal device, information used to indicate an associationrelationship between one or more random access occasions (ROs) and asynchronization signal block; and accessing, by the terminal device, anetwork device based on the information on an RO corresponding to thesynchronization signal block index information; where the associationrelationship between an RO and a synchronization signal block is atleast one of the following: a quantity of synchronization signal blocksassociated with one RO is at least 1/F, or is P at most, where F is aquantity of ROs in frequency domain, and P is related to a quantity ofactually transmitted synchronization signal blocks; and/or Nsynchronization signal blocks or N synchronization signal block groupsare associated with one RO in frequency domain or are associated withall ROs in frequency domain; and/or the first random access channel(RACH) resources in every X RACH resource configuration periods Y areassociated with same synchronization signal blocks when one randomaccess resource configuration period is P, where P and X are integersand Y is equal to P multiplied by X. The terminal device may obtain thedownlink synchronization signal block index information in the followingmanner: The terminal device receives a downlink synchronization signalblock, where the downlink synchronization signal block carries indexinformation. In this aspect, a time-frequency location of a randomaccess resource associated with each downlink synchronization signal isindicated, so that the terminal device obtains, through downlinksynchronization, a time-frequency location for sending an uplink randomaccess signal, to avoid a blind attempt of the terminal device and abeam mismatch of the network device occurring when the network devicereceives a random access signal, thereby improving efficiency.

In a possible implementation, when the association relationship is thatN synchronization signal blocks or N synchronization signal block groupsare associated with one RO in frequency domain or are associated withall ROs in frequency domain, the method further includes: receiving, bythe terminal device, indication information from the network device,where the indication information is used to indicate that the Nsynchronization signal blocks or the N synchronization signal blockgroups are associated with one RO in frequency domain, or is used toindicate that the N synchronization signal blocks or the Nsynchronization signal block groups are associated with all the ROs infrequency domain.

In another possible implementation, when one random access resourceconfiguration period is P, and the first RACH resources in every X RACHresource configuration periods are associated with same synchronizationsignal blocks, X is received from the network device or is prestored;and/or Y is received from the network device or is prestored.

In still another possible implementation, a value of Y is 10 ms, 20 ms,40 ms, 80 ms, 160 ms, 320 ms, or 640 ms.

In yet another possible implementation, a value of X is related to aquantity of synchronization signal blocks, or a value of X is related toa quantity of random access resources in one random access resourceconfiguration period, or a value of X is 1, 2, 4, 8, or 16.

In still yet another possible implementation, when one random accessresource configuration period is P, and the first random accessresources in every X random access resource configuration periods areassociated with same synchronization signal blocks, if there are one ormore remaining random access resources, the terminal device does notaccess the network device on the remaining random access resource.

In a further possible implementation, when one random access resourceconfiguration period is P, and the first random access resources inevery X random access resource configuration periods are associated withsame synchronization signal blocks, if there are one or more remainingrandom access resources, the one or more remaining random accessresources are associated starting from the first synchronization signalblock or the last synchronization signal block or a next synchronizationsignal block of an end synchronization signal block in previous Xperiods, or any one or more of the foregoing three associationrelationships are used in different X periods.

In a still further possible implementation, when the associationrelationship is that N synchronization signal blocks or Nsynchronization signal block groups are associated with one RO infrequency domain or are associated with all ROs in frequency domain, ifa quantity N of actually transmitted synchronization signal blocks orsynchronization signal block groups cannot be exactly divided by aquantity, configured by the network device, of synchronization signalblocks associated with one RO, after a quantity of synchronizationsignal blocks or synchronization signal block groups are associated witha corresponding RO, where the quantity is an integer multiple of thequantity configured by the network device, a remaining synchronizationsignal block or downlink synchronization signal block group isassociated with another one or more ROs. N is 1 or above.

In a yet further possible implementation, a quantity of random accessresources in a random access resource configuration period or a randomaccess resource association period is related to a quantity ofsynchronization signal blocks or synchronization signal block groups.

Correspondingly, a communications apparatus is provided and canimplement the foregoing communications method. For example, thecommunications apparatus may be a chip (such as a baseband chip or acommunications chip) or a device (such as a terminal device). Thecommunications apparatus may implement the foregoing method by usingsoftware or hardware, or by using hardware executing correspondingsoftware.

In a possible implementation, a structure of the communicationsapparatus includes a processor and a memory. The processor is configuredto support the apparatus in executing a corresponding function in theforegoing communications method. The memory is configured to couple withthe processor, and the memory stores a program (an instruction) and/ordata necessary for the apparatus. Optionally, the communicationsapparatus may further include a communications interface, configured tosupport communication between the apparatus and another network element.

In another possible implementation, the communications apparatus mayinclude a receiving unit and a processing unit. The receiving unit isconfigured to implement a receiving function in the foregoing method.The processing unit is configured to implement a processing function inthe foregoing method. For example, the receiving unit is configured toreceive a downlink signal, where the downlink signal carries downlinksynchronization signal block index information. The receiving unit isfurther configured to receive information used to indicate anassociation relationship between a random access occasion RO and asynchronization signal block. The processing unit is configured toobtain the synchronization signal block index information and theassociation relationship between a random access occasion RO and asynchronization signal block from the receiving unit, and access anetwork device on an RO corresponding to the synchronization signalblock index information. The association relationship between an RO anda synchronization signal block is at least one of the following: aquantity of synchronization signal blocks associated with one RO is atleast 1/F, or is P at most, where F is a quantity of ROs in frequencydomain, and P is related to a quantity of actually transmittedsynchronization signal blocks; and/or N synchronization signal blocks orN synchronization signal block groups are associated with one RO infrequency domain or are associated with all ROs in frequency domain;and/or the first RACH resources in every X RACH resource configurationperiods Y are associated with same synchronization signal blocks whenone random access resource configuration period is P, where P and X areintegers and Y is equal to P multiplied by X. The processing unit mayobtain the synchronization signal block index information in thefollowing manner: The receiving unit receives a synchronization signalblock, where the synchronization signal block carries index information,and the processing unit obtains the index information of thesynchronization signal block from the receiving unit.

When the communications apparatus is a chip, the receiving unit may bean input unit, for example, an input circuit or an input communicationsinterface; and a sending unit may be an output unit, for example, anoutput circuit or an output communications interface. When thecommunications apparatus is a device, the receiving unit may be areceiver; and the sending unit may be a transmitter.

According to another aspect of this application, a communications methodis provided, including: sending, by a network device, downlinksynchronization signal block index information to a terminal device;sending, by the network device to the terminal device, information usedto indicate an association relationship between a random access resourceRO and a synchronization signal block; and receiving, by the networkdevice, a random access signal that is sent by the terminal device on anRO corresponding to the synchronization signal block index information.In this aspect, a time-frequency location of a random access resourceassociated with each downlink synchronization signal is indicated, sothat the terminal device obtains, through downlink synchronization, atime-frequency location for sending an uplink random access signal, toavoid a blind attempt of the terminal device and a beam mismatch of thenetwork device occurring when the network device receives a randomaccess signal, thereby improving efficiency.

Correspondingly, a communications apparatus is provided and canimplement the foregoing communications method. For example, thecommunications apparatus may be a chip (such as a baseband chip or acommunications chip) or a device (such as a network device or a basebandprocessing board). The communications apparatus may implement theforegoing method by using software or hardware, or by using hardwareexecuting corresponding software.

In a possible implementation, a structure of the communicationsapparatus includes a processor and a memory. The processor is configuredto support the apparatus in executing a corresponding function in theforegoing communications method. The memory is configured to couple withthe processor, and the memory stores a program (an instruction) and datanecessary for the apparatus. Optionally, the communications apparatusmay further include a communications interface, configured to supportcommunication between the apparatus and another network element.

In another possible implementation, the communications apparatus mayinclude a receiving unit and a sending unit. The receiving unit and thesending unit are configured to respectively implement a receivingfunction and a sending function in the foregoing method. For example,the sending unit is configured to send downlink synchronization signalblock index information to a terminal device. The sending unit isfurther configured to send, to the terminal device, information used toindicate an association relationship between a random access resource ROand a synchronization signal block. The receiving unit is configured toreceive a random access signal that is sent by the terminal device on anRO corresponding to the synchronization signal block index information.

When the communications apparatus is a chip, the receiving unit may bean input unit, for example, an input circuit or an input communicationsinterface; and the sending unit may be an output unit, for example, anoutput circuit or an output communications interface. When thecommunications apparatus is a device, the receiving unit may be areceiver; and the sending unit may be a transmitter.

According to still another aspect of this application, a communicationsmethod is provided, including: receiving, by a terminal device, firstinformation and/or second information sent by a network device, wherethe first information is used to instruct to send a first uplink signalon a first time-frequency resource; and/or the second information isused to instruct to send a second uplink signal on a secondtime-frequency resource; and when a third time-frequency resource in thefirst time-frequency resource indicated by the first information isincluded in the second time-frequency resource indicated by the secondinformation, sending, by the terminal device, the first uplink signal tothe network device on a time-frequency resource other than the thirdtime-frequency resource in the first time-frequency resource; or when afourth time-frequency resource in the second time-frequency resourceindicated by the second information is included in the firsttime-frequency resource indicated by the first information, sending, bythe terminal device, the second uplink signal to the network device on atime-frequency resource other than the fourth time-frequency resource inthe second time-frequency resource; or when a third time-frequencyresource in the first time-frequency resource indicated by the firstinformation overlaps a fourth time-frequency resource in the secondtime-frequency resource indicated by the second information, sending, bythe terminal device, the first uplink signal to the network device onthe first time-frequency resource, and/or sending, by the terminaldevice, the second uplink signal to the network device on the secondtime-frequency resource. In this aspect, the terminal device sends anuplink signal based on time-frequency resource indication information.In this way, a time-frequency resource conflict between uplink signalscan be avoided and signal receiving performance is improved.

In a possible implementation, the first uplink signal is at least one ofthe following: a periodic signal, a semi-static signal, asemi-persistent signal, a periodic sounding reference signal, a periodicdemodulation reference signal, a periodic physical uplink shared channelsignal, a periodic physical uplink control channel signal, and a dynamicscheduling/configuration signal; and the second uplink signal is arandom access signal.

In another possible implementation, the receiving, by a terminal device,first information and/or second information sent by a network devicespecifically includes: receiving, by the terminal device by using atleast one type of the following information, the first informationand/or the second information sent by the network device, where the atleast one type of the following information includes: systeminformation, radio resource control signaling, a downlink controlchannel, and a Media Access Control control element (MAC CE).

In still another possible implementation, the method further includes:receiving, by the terminal device, third information, where the thirdinformation includes an uplink signal transmission precoding type, andthe uplink signal transmission precoding type includes a first type anda second type; and sending, by the terminal device, an uplink signal tothe network device based on the first information, the secondinformation, and the third information.

In yet another possible implementation, the method further includes:when the uplink signal transmission precoding type is the first type,and/or the third time-frequency resource in the first time-frequencyresource indicated by the first information overlaps the fourthtime-frequency resource in the second time-frequency resource indicatedby the second information, sending, by the terminal device, the firstuplink signal to the network device on the first time-frequencyresource, and/or sending, by the terminal device, the second uplinksignal to the network device on the second time-frequency resource; orwhen the uplink signal transmission precoding type is the second type,and the third time-frequency resource in the first time-frequencyresource indicated by the first information is included in the secondtime-frequency resource indicated by the second information, sending, bythe terminal device, the first uplink signal to the network device on atime-frequency resource other than the third time-frequency resource inthe first time-frequency resource; or when the uplink signaltransmission precoding type is the second type, and the fourthtime-frequency resource in the second time-frequency resource indicatedby the second information is included in the first time-frequencyresource indicated by the first information, sending, by the terminaldevice, the second uplink signal to the network device on atime-frequency resource other than the fourth time-frequency resource inthe second time-frequency resource.

Correspondingly, a communications apparatus is provided and canimplement the foregoing communications method. For example, thecommunications apparatus may be a chip (such as a baseband chip or acommunications chip) or a device (such as a terminal device). Thecommunications apparatus may implement the foregoing method by usingsoftware or hardware, or by using hardware executing correspondingsoftware.

In a possible implementation, a structure of the communicationsapparatus includes a processor and a memory. The processor is configuredto support the apparatus in executing a corresponding function in theforegoing communications method. The memory is configured to couple withthe processor, and the memory stores a program (an instruction) and/ordata necessary for the apparatus. Optionally, the communicationsapparatus may further include a communications interface, configured tosupport communication between the apparatus and another network element.

In another possible implementation, the communications apparatus mayinclude a sending unit, a receiving unit, and a processing unit. Thesending unit and the receiving unit are configured to respectivelyimplement a sending function and a receiving function in the foregoingmethod. The processing unit is configured to implement a processingfunction in the foregoing method. For example, the receiving unit isconfigured to receive first information and/or second information sentby a network device, where the first information is used to instruct tosend a first uplink signal on a first time-frequency resource; and/orthe second information is used to instruct to send a second uplinksignal on a second time-frequency resource; and the sending unit isconfigured to: when a third time-frequency resource in the firsttime-frequency resource indicated by the first information is includedin the second time-frequency resource indicated by the secondinformation, send the first uplink signal to the network device on atime-frequency resource other than the third time-frequency resource inthe first time-frequency resource; or further configured to: when afourth time-frequency resource in the second time-frequency resourceindicated by the second information is included in the firsttime-frequency resource indicated by the first information, send thesecond uplink signal to the network device on a time-frequency resourceother than the fourth time-frequency resource in the secondtime-frequency resource; or further configured to: when a thirdtime-frequency resource in the first time-frequency resource indicatedby the first information overlaps a fourth time-frequency resource inthe second time-frequency resource indicated by the second information,send the first uplink signal to the network device on the firsttime-frequency resource, and/or send the second uplink signal to thenetwork device on the second time-frequency resource.

When the communications apparatus is a chip, the receiving unit may bean input unit, for example, an input circuit or an input communicationsinterface; and the sending unit may be an output unit, for example, anoutput circuit or an output communications interface. When thecommunications apparatus is a device, the receiving unit may be areceiver; and the sending unit may be a transmitter.

According to yet another aspect of this application, a communicationsmethod is provided, including: sending, by a network device, firstinformation and/or second information to a terminal device, where thefirst information is used to instruct to send a first uplink signal on afirst time-frequency resource; and/or the second information is used toinstruct to send a second uplink signal on a second time-frequencyresource; and when a third time-frequency resource in the firsttime-frequency resource indicated by the first information is includedin the second time-frequency resource indicated by the secondinformation, receiving, by the network device, the first uplink signalthat is sent by the terminal device on a time-frequency resource otherthan the third time-frequency resource in the first time-frequencyresource; or when a fourth time-frequency resource in the secondtime-frequency resource indicated by the second information is includedin the first time-frequency resource indicated by the first information,receiving, by the network device, the second uplink signal that is sentby the terminal device on a time-frequency resource other than thefourth time-frequency resource in the second time-frequency resource; orwhen a third time-frequency resource in the first time-frequencyresource indicated by the first information overlaps a fourthtime-frequency resource in the second time-frequency resource indicatedby the second information, receiving, by the network device, the firstuplink signal that is sent by the terminal device on the firsttime-frequency resource, and/or receiving, by the network device, thesecond uplink signal that is sent by the terminal device on the secondtime-frequency resource. In this aspect, the terminal device sends anuplink signal based on time-frequency resource indication information.In this way, a time-frequency resource conflict between uplink signalscan be avoided and signal receiving performance of the network device isimproved.

In a possible implementation, the method further includes: sending, bythe network device, third information to the terminal device, where thethird information includes an uplink signal transmission precoding type,and the uplink signal transmission precoding type includes a first typeand a second type; and receiving, by the network device, an uplinksignal that is sent by the terminal device based on the firstinformation, the second information, and the third information.

In another possible implementation, the method further includes: whenthe uplink signal transmission precoding type is the first type, and/orthe third time-frequency resource in the first time-frequency resourceindicated by the first information overlaps the fourth time-frequencyresource in the second time-frequency resource indicated by the secondinformation, receiving, by the network device, the first uplink signalthat is sent by the terminal device on the first time-frequencyresource, and/or receiving, by the network device, the second uplinksignal that is sent by the terminal device on the second time-frequencyresource; or when the uplink signal transmission precoding type is thesecond type, and the third time-frequency resource in the firsttime-frequency resource indicated by the first information is includedin the second time-frequency resource indicated by the secondinformation, receiving, by the network device, the first uplink signalthat is sent by the terminal device on a time-frequency resource otherthan the third time-frequency resource in the first time-frequencyresource; or when the uplink signal transmission precoding type is thesecond type, and the fourth time-frequency resource in the secondtime-frequency resource indicated by the second information is includedin the first time-frequency resource indicated by the first information,receiving, by the network device, the second uplink signal that is sentby the terminal device on a time-frequency resource other than thefourth time-frequency resource in the second time-frequency resource.

Correspondingly, a communications apparatus is provided and canimplement the foregoing communications method. For example, thecommunications apparatus may be a chip (such as a baseband chip or acommunications chip) or a device (such as a network device or a basebandprocessing board). The communications apparatus may implement theforegoing method by using software or hardware, or by using hardwareexecuting corresponding software.

In a possible implementation, a structure of the communicationsapparatus includes a processor and a memory. The processor is configuredto support the apparatus in executing a corresponding function in theforegoing communications method. The memory is configured to couple withthe processor, and the memory stores a program (an instruction) and datanecessary for the apparatus. Optionally, the communications apparatusmay further include a communications interface, configured to supportcommunication between the apparatus and another network element.

In another possible implementation, the communications apparatus mayinclude a receiving unit and a sending unit. The receiving unit and thesending unit are configured to respectively implement a receivingfunction and a sending function in the foregoing method. For example,the sending unit is configured to send first information and/or secondinformation to a terminal device, where the first information is used toinstruct to send a first uplink signal on a first time-frequencyresource; and/or the second information is used to instruct to send asecond uplink signal on a second time-frequency resource; and when athird time-frequency resource in the first time-frequency resourceindicated by the first information is included in the secondtime-frequency resource indicated by the second information, thereceiving unit is configured to receive the first uplink signal that issent by the terminal device on a time-frequency resource other than thethird time-frequency resource in the first time-frequency resource; orwhen a fourth time-frequency resource in the second time-frequencyresource indicated by the second information is included in the firsttime-frequency resource indicated by the first information, thereceiving unit is further configured to receive the second uplink signalthat is sent by the terminal device on a time-frequency resource otherthan the fourth time-frequency resource in the second time-frequencyresource; or when a third time-frequency resource in the firsttime-frequency resource indicated by the first information overlaps afourth time-frequency resource in the second time-frequency resourceindicated by the second information, the receiving unit is furtherconfigured to receive the first uplink signal that is sent by theterminal device on the first time-frequency resource, and/or thereceiving unit is further configured to receive the second uplink signalthat is sent by the terminal device on the second time-frequencyresource.

When the communications apparatus is a chip, the receiving unit may bean input unit, for example, an input circuit or an input communicationsinterface; and the sending unit may be an output unit, for example, anoutput circuit or an output communications interface. When thecommunications apparatus is a device, the receiving unit may be areceiver; and the sending unit may be a transmitter.

According to still yet another aspect of this application, acomputer-readable storage medium is provided. The computer-readablestorage medium stores an instruction, and when the instruction is run ona computer, the computer is enabled to perform the method according tothe foregoing aspects.

According to a further aspect of this application, a computer programproduct including an instruction is provided, and when the computerprogram product is run on a computer, the computer is enabled to performthe method according to the foregoing aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

To describe the technical solutions in the embodiments of thisapplication or in the background more clearly, the following brieflydescribes the accompanying drawings required for describing theembodiments of this application or the background.

FIG. 1 is a schematic diagram of a communications system to which thisapplication is applicable;

FIG. 2a is a schematic diagram of sending of downlink signals;

FIG. 2b is a schematic diagram of random access signal receivingperformed through time division;

FIG. 3 is a schematic diagram of an interaction process of acommunications method according to an embodiment of this application;

FIG. 4a to FIG. 4e are schematic diagrams of association between arandom access occasion and a synchronization signal block or asynchronization signal block group in an example of this application;

FIG. 5 is a schematic diagram of an interaction process of anothercommunications method according to an embodiment of this application;

FIG. 6 is a schematic diagram of an indication of an actuallytransmitted synchronization signal block or synchronization signal blockgroup;

FIG. 7 is a schematic structural diagram of a communications apparatusaccording to an embodiment of this application;

FIG. 8 is a schematic structural diagram of another communicationsapparatus according to an embodiment of this application;

FIG. 9 is a schematic structural diagram of still another communicationsapparatus according to an embodiment of this application;

FIG. 10 is a schematic structural diagram of yet another communicationsapparatus according to an embodiment of this application;

FIG. 11 is a schematic structural diagram of hardware of acommunications apparatus according to an embodiment of this application;and

FIG. 12 is a schematic structural diagram of hardware of anothercommunications apparatus according to an embodiment of this application.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The following describes embodiments of this application with referenceto the accompanying drawings in the embodiments of this application.

As shown in a schematic diagram of a communications system in FIG. 1, asolution in this application is applicable to the communications system.The communications system may include at least one network device (onlyone network device is shown, for example, a gNB in the figure) and oneor more terminal devices connected to the network device (four UEs areshown in the figure: UE1 to UE4).

The network device may be a device that can communicate with theterminal device. The network device may be any device with a wirelesssending and receiving function. The network device includes but is notlimited to a base station (for example, a NodeB, an evolved NodeB(eNodeB), a base station in a 5th generation (5G) communications system,a base station or a network device in a future communications system, oran access node, a wireless relay node, or a wireless backhaul node in aWi-Fi system). Alternatively, the network device may be a radiocontroller in a cloud radio access network (CRAN) scenario.Alternatively, the network device may be a network device in a 5Gnetwork or a network device in a future evolved network; or may be awearable device, an in-vehicle device, or the like. Alternatively, thenetwork device may be a small cell, a transmission node (transmissionreception point, TRP), or the like. Certainly, this application is notlimited thereto.

The terminal device is a device with a wireless sending and receivingfunction. The terminal device may be deployed on land and includes anindoor or outdoor device, a hand-held device, a wearable device, or anin-vehicle device, may be deployed on a water surface (for example, aship), or may be deployed in the air (for example, an airplane, aballoon, or a satellite). The terminal device may be a mobile phone(mobile phone), a tablet computer (Pad), a computer having a wirelesssending and receiving function, a virtual reality (VR) terminal device,an augmented reality (AR) terminal device, a wireless terminal relatedto industrial control, a wireless terminal related to self-driving, awireless terminal related to remote medical, a wireless terminal relatedto a smart grid, a wireless terminal related to transportation safety, awireless terminal related to a smart city, a wireless terminal relatedto a smart home, or the like. An application scenario is not limited inthe embodiments of this application. Sometimes, the terminal device mayalternatively be referred to as user equipment (UE), an access terminaldevice, a UE unit, a UE station, a mobile station, a mobile console, aremote station, a remote terminal device, a mobile device, a UE terminaldevice, a terminal device, a terminal, a wireless communications device,a UE agent, a UE apparatus, or the like.

It should be noted that the terms “system” and “network” may be usedinterchangeably in the embodiments of this application. The term “aplurality of” means two or more than two. In view of this, the term “aplurality of” may also be understood as “at least two” in theembodiments of this application. The term “and/or” describes anassociation relationship for describing associated objects andrepresents that three relationships may exist. For example, A and/or Bmay represent the following three cases: Only A exists, both A and Bexist, and only B exists. In addition, the character “/” usuallyrepresents an “or” relationship between the associated objects unlessotherwise specified.

As shown in FIG. 1, a base station implements cell coverage by using aplurality of beams. The base station needs a suitable beam direction tocommunicate with a terminal device, for example, to receive a randomaccess preamble signal or send a random access response. In a downlinksynchronization process, the terminal device may obtain a base stationtransmit beam and a terminal receive beam for sending a downlink signal.In a sending and receiving process of an uplink random access signal,the base station may obtain a signal sent in an uplink and a basestation receive beam. An association relationship exists between adownlink signal and a random access resource/preamble to improveefficiency.

The embodiments of this application provide a communications method andapparatus. A time-frequency location of a random access resourceassociated with each downlink synchronization signal is indicated, sothat a terminal device obtains, through downlink synchronization, atime-frequency location for sending an uplink random access signal, toavoid a blind attempt of the terminal device and a beam mismatch of anetwork device occurring when the network device receives a randomaccess signal, thereby improving efficiency.

FIG. 2a is a schematic diagram of sending of downlink signals. Thedownlink signals are sent in a time division manner. To be specific,different downlink signals are sent at different times. For example, adownlink signal is a downlink synchronization signal block (SS/PBCHblock), and the synchronization signal block is identified by using asynchronization signal block index SS/PBCH block index. The downlinksignal may be one or more synchronization signal blocks.

FIG. 2b is a schematic diagram of random access signal receivingperformed through time division. To be specific, random access signals(associated with different downlink signals) are received at differenttimes. Random access signals in a plurality of directions may beseparately received at a same time based on an implementation capabilityof a network device (for example, the network device first uses antennaelements in an antenna array to receive signals in various directions,and uses digital-domain beamforming to generate a plurality of receivebeams and obtain signals in directions of the receive beams).

In this application, for ease of description, a random access resourceor a random access resource preamble is referred to as a “random accessresource/preamble” for short. In other words, the random access resourceincludes time and frequency resources used for random access and aset/subset of random access preambles on random access time andfrequencies resources. A random access occasion (RACH occasion/RACHtransmission occasion/RACH opportunity/RACH chance/PRACH occasion, ROfor short) is time and frequency resources for sending one random accesspreamble. A random access resource may be an RO, or one random accesspreamble set on an RO, or a combination of a random access preamble anda timing. A terminal device can send one random access preamble signalon this resource.

“Fixed” in this application means stipulated by a protocol or agreed onbetween a network device and a terminal device.

An index in this application starts from 0, or may start from 1 in anactual situation. When the index starts from 1, an index starting from 0is automatically incremented by 1.

The RO resource in this application represents a time resource and afrequency resource of a random access timing.

A synchronization signal block (SS/PBCH block) in this application isreferred to as an SSB for short, and a synchronization signal blockgroup (SS/PBCH block group) is referred to as an SSB group for short.One SSB group includes one or more SSBs.

For ease of description, descriptions of a random access occasion (RO),a synchronization signal block (SS/PBCH block or SSB), and asynchronization signal block group (SS/PBCH block group, or SSB group)are intended to indicate one or above, instead of a limitation to onlyone, unless a quantity of random access occasions, a quantity ofsynchronization signal blocks, or a quantity of synchronization signalblock groups is otherwise explicitly emphasized.

This application provides four methods for assigning a serial number fora synchronization signal block (SS/PBCH block, SSB). The serial numbermay sometimes be referred to as an index, used to identify the SSB.

In a first numbering method, all actually transmitted SSBs are numbered,without differentiating between actually transmitted synchronizationsignal block groups (SS/PBCH block group, SSB group for short). Forexample, 49 SSBs are actually transmitted, and the 49 SSBs are numbered0 to 48.

In a second numbering method, an actually transmitted SSB group and anSSB inside the actually transmitted SSB group are separately numberedfor expression. For example, 8 SSB groups are actually transmitted, andthe 8 SSB groups are numbered 0 to 7. SSBs in each SSB group also haveserial numbers. For example, an SSB group has 8 SSBs, and the 8 SSBs arenumbered 0 to 7.

In a third numbering method, all possibly transmitted SSBs are numbered,without differentiating between possibly transmitted SSB groups. Forexample, if 64 SSBs are possibly transmitted, the SSBs are numbered 0 to63.

In a fourth numbering method, a possibly transmitted SSB group and anSSB inside the possibly transmitted SSB group are separately numberedfor expression. For example, there are 9 SSB groups and the 9 SSB groupsare numbered 0 to 8. SSBs in each possibly transmitted SSB group alsohave serial numbers. For example, an SSB group has 9 SSBs, and the 9SSBs are numbered 0 to 8.

The foregoing synchronization signal block may be a synchronizationsignal block in a half-frame for transmitting a synchronization signalblock. It should be noted that, the synchronization signal block orsynchronization signal block group mentioned in this application may bea possibly transmitted synchronization signal block or synchronizationsignal block group, or may be an actually transmitted synchronizationsignal block or synchronization signal block group. There may be one ormore possibly transmitted synchronization signal blocks orsynchronization signal block groups. There may be one or more actuallytransmitted synchronization signal blocks or synchronization signalblock groups.

Configuring information by a network device or a base station mentionedin this application may be performed by using at least one of an MIB,remaining minimum system information (RMSI), system information block(SIB)1, SIB2, downlink control information (downlink controlinformation, DCI), radio resource control (RRC) signaling, and a MediaAccess Control control element (MAC-CE).

A group, a set, and a category mentioned in this application aredifferent expressions of a same concept.

A random access preamble group mentioned in this application may be arandom access preamble direct subset, or may mean the following: Prandom access preamble sequences are mapped to different synchronizationsignal blocks or mapped to different synchronization signal blockgroups, and a quantity of groups thereof or a quantity of subsetsthereof is related to a quantity of synchronization signal blocks orrelated to a quantity of synchronization signal block groups.

Mod indicates calculating a remainder, floor indicates rounding down toa nearest integer, and ceil indicates rounding up to a nearest integer.

Meanings of mapping and association are the same.

FIG. 3 is a schematic diagram of an interaction process of acommunications method according to an embodiment of this application.The method may include the following steps:

S301: A network device sends synchronization signal block indexinformation to a terminal device. The terminal device obtains thesynchronization signal block index information. For example, the networkdevice sends a synchronization signal block to the terminal device,where the synchronization signal block index information is implicitlycarried in the synchronization signal block.

S302: The network device sends, to the terminal device, information usedto indicate an association relationship between a random access resourceRO and a synchronization signal block. The terminal device receives theindication information.

S303: The terminal device accesses the network device based on theinformation on an RO corresponding to the synchronization signal blockindex information. The network device receives a random access signalsent by the terminal device.

The network device sends a downlink signal (for example, thesynchronization signal block) to the terminal device to perform downlinksynchronization. The synchronization signal block index information iscarried when the downlink signal is sent. The synchronization signalblock index information is used to identify the synchronization signalblock, and for example, is a serial number of the synchronization signalblock, an index of the synchronization signal block, or otherinformation available for identifying the synchronization signal block.One synchronization signal block includes one primary synchronizationsignal (PSS) symbol, one secondary synchronization signal (SSS) symbol,and two physical broadcast channel (PBCH) symbols.

In addition, the network device further sends, to the terminal device,the information used to indicate an association relationship between arandom access resource RO and a synchronization signal block.

It should be noted that, the synchronization signal block indexinformation and the information indicating an association relationshipmay be sent by the network device at the same time in one piece ofconfiguration information, or may be separately sent by the networkdevice. The two steps described herein do not necessarily mean that theyare sent separately.

The association relationship between an RO and a synchronization signalblock is at least one of the following:

a quantity of synchronization signal blocks associated with one RO is atleast 1/F, or is P at most, where F is a quantity of ROs in frequencydomain, and P is related to a quantity of actually transmitted downlinksynchronization signal blocks; and/or

N synchronization signal blocks or N synchronization signal block groupsare associated with one RO in frequency domain or are associated withall ROs in frequency domain; and/or

the first RACH resources in every X RACH resource configuration periodsY are associated with same synchronization signal blocks orsynchronization signal block groups when one random access resourceconfiguration period is P, where P and X are integers and Y is equal toP multiplied by X.

The association relationship between an RO and a synchronization signalblock is described in detail below.

The terminal device accesses the network device based on the associationrelationship between an RO and a synchronization signal block on the ROcorresponding to the synchronization signal block index information. Forexample, the terminal device sends a random access signal to the networkdevice, and the network device receives the random access signal sent bythe terminal device.

The network device knows a status of a random access receive beamcorresponding to a downlink signal/transmit beam coverage area, andassigns a random access resource time-frequency location for eachdownlink signal, so that the terminal device obtains, through downlinksynchronization, a time-frequency location for sending an uplink randomaccess signal, to avoid a blind attempt of the terminal device and abeam mismatch of the network device occurring when the network devicereceives a random access signal, thereby improving efficiency.

Specifically, the association relationship between an RO and asynchronization signal block is described below:

One association relationship is that a quantity of synchronizationsignal blocks associated with one RO is at least 1/F, or is P at most,where F is a quantity of ROs in frequency domain, and P is related to aquantity of actually transmitted synchronization signal blocks.

In this association relationship, the quantity of ROs in frequencydomain and a quantity of synchronization signal blocks orsynchronization signal block groups associated with one RO are jointlyconfigured.

In specific implementation, the quantity N of synchronization signalblocks associated with one RO may be related to F. For example, thequantity N may be a multiple of 1/F; or the quantity N may be 1/F, inother words, one synchronization signal block may be associated with allof F ROs; or the quantity N may be a fractional multiple of F. F is thequantity of ROs in frequency domain, and a value of F may be 1, 2, 4, 6,or 8. The network device may define or configure a minimum quantity ofsynchronization signal blocks associated with one RO as 1/F. A value ofN may also be defined based on F. For example, when F=1, the value of Nmay be 1, 2, 3, 4, . . . , Y1, where Y1 is a maximum quantity of SS/PBCHblocks associated with one RO; when F=2, the value of N may be ½, 1, 2,3, 4, . . . , Y1; when F=4, the value of N may be ¼, ½, 1, 2, 3, 4, . .. , Y1; when F=6, the value of N may be ⅙, ⅓, ½, 1, 2, 3, 4, . . . , Y1;when=8, the value of N may be ⅛, ¼, ½, 1, 2, 3, 4, . . . , Y1.

The value of N may also be related to a quantity of synchronizationsignal blocks actually transmitted in a half-frame, for example, afactor of the quantity of actually transmitted synchronization signalblocks.

Another association relationship is that N synchronization signal blocksor N synchronization signal block groups are associated with one RO infrequency domain or are associated with all ROs in frequency domain.

In specific implementation, the N synchronization signal blocks orsynchronization signal block groups may be associated with all of F ROs.F may be a value greater than or equal to 1. A value of N may be some orall values of 1 to 8. When the value of N is some of the values, thevalue of N may be 1, may be 1 or 2, may be 1, 2, or 3, or may be 1, 2,3, or 4. The N synchronization signal blocks or synchronization signalblock groups may be associated with one frequency division multiplexedRO, or may be associated with some frequency division multiplexed ROs.The network device may instruct to associate the N synchronizationsignal blocks or downlink synchronization signal block groups with allof the F ROs or with one RO in frequency domain. The F ROs may befrequency division multiplexed ROs of a same time.

When a quantity N2 of actually transmitted synchronization signal blocksor synchronization signal block groups is less than a quantity N,configured by the network device, of synchronization signal blocks orsynchronization signal block groups associated with one RO, all of the Nsynchronization signal blocks or downlink synchronization signal blockgroups may be associated with one corresponding RO. For example, if thequantity of actually transmitted synchronization signal blocks is 5 andthe quantity, configured by the network device, of synchronizationsignal blocks associated with one RO is 8, all of the 5 synchronizationsignal blocks are associated with the RO.

When a quantity N of actually transmitted synchronization signal blocksor synchronization signal block groups cannot be exactly divided by aquantity M, configured by the network device, of synchronization signalblocks or synchronization signal block groups associated with one RO,after a quantity of synchronization signal blocks or synchronizationsignal block groups are associated with a corresponding to RO, where thequantity is an integer multiple of the quantity M configured by thenetwork device, a remaining synchronization signal block orsynchronization signal block group is associated with another one ormore ROs. For example, it is assumed that K1=floor(N/M) and first K1×Mof N synchronization signal blocks are associated with K1 correspondingROs; in this case, N−K1×M final remaining synchronization signal blocksor synchronization signal block groups are associated with another oneor more ROs, as shown in FIG. 4a . Alternatively, last K1×M of Nsynchronization signal blocks are associated with K1 corresponding ROs;in this case, N−K1×M remaining synchronization signal blocks orsynchronization signal block groups are associated with another one ormore ROs. Alternatively, a remaining synchronization signal block may benot associated, or synchronization signal blocks or synchronizationsignal block groups may be cyclically associated with ROs, as shown inFIG. 4b . When F ROs are associated with one synchronization signalblock, the F ROs may be F ROs in one RO configuration period or F ROs inone RO association period. Alternatively, an averaging method may beused. For example, a quantity, configured by the network device, ofsynchronization signal blocks or synchronization signal block groupsassociated with one RO is N2, a quantity of actually transmittedsynchronization signal blocks or synchronization signal block groups isM2, and a quantity of ROs that can be associated is K1; in this case, aquantity M3 of actually transmitted synchronization signal blocks orsynchronization signal block groups that are associated with one RO maybe M2/K1, where a value of M3 may be an average value less than N2. Forexample, a maximum quantity of synchronization signal blocks orsynchronization signal block groups associated with one RO is 8, aquantity of actually transmitted downlink synchronization signal blocksor synchronization signal block groups is 12, and 2 or 3 ROs may beassociated. When 2 ROs are associated, a quantity of synchronizationsignal blocks or synchronization signal block groups associated witheach RO is 6.

Further, when the association relationship is that N synchronizationsignal blocks or N synchronization signal block groups are associatedwith one RO in frequency domain or are associated with all ROs infrequency domain, the method further includes:

receiving, by the terminal device, indication information from thenetwork device, where the indication information is used to indicatethat the N synchronization signal blocks or the N synchronization signalblock groups are associated with one RO in frequency domain, or is usedto indicate that the N synchronization signal blocks or the Nsynchronization signal block groups are associated with all the ROs infrequency domain.

Still another association relationship is that the first RACH resourcesin every X RACH resource configuration periods Y are associated withsame synchronization signal blocks or synchronization signal blockgroups when one random access resource configuration period is P, whereP and X are integers and Y is equal to P multiplied by X.

This method for associating a RACH resource with a synchronizationsignal block or synchronization signal block group is a cyclicassociation method. A parameter X is set, and the first RACH resourcesin X RACH resource configuration periods are associated with samesynchronization signal blocks. In other words, an associationrelationship in every X RACH resource configuration period isre-calculated. The X RACH resource configuration period may be referredto as one random access period. X may be fixed in a protocol, forexample, may be any value in 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14, 15, and 16, for example, may be 1, 8, or 16. X may be received fromthe network device or may be prestored. A quantity of random accessresources in one random access resource configuration period or onerandom access resource association period is related to a quantity ofdownlink synchronization signal blocks or downlink synchronizationsignal block groups. A value of X may be configured, and may be some orall values in 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16.

The random access resource association period may be understood as anamount of time or a time width occupied by a random access resourceassociated with a synchronization signal block, or a quantity of ROsassociated with a sent downlink synchronization signal block. The firstRO is associated with the first sent synchronization signal block ineach of different association periods. Alternatively, the first randomaccess resource is associated with the first sent synchronization signalblock in each of different time periods for association.

The random access resource configuration period is also referred to as arandom access configuration period, and is a time interval at which arandom access resource repeatedly occurs, or includes at least a timeinterval at which random access resources in one complete random accessresource association period repeatedly occur.

The X RACH resource configuration periods may also be fixed to Y ms. Avalue of Y may be 10, 20, 40, 80, 160, 320, or 640. It should be notedthat, the network device may pre-configure a plurality of values of Y.In an actual application, the network device may select one of thevalues of Y, or may dynamically configure one value of Y at a time. Thevalue of X is determined based on the RACH resource configurationperiod. For example, Y=160, and the RACH resource configuration periodis 40 ms; in this case, X=4. Y may be received from the network deviceor may be prestored.

Alternatively, the value of X or Y may be determined based on thequantity of actually transmitted synchronization signal blocks orsynchronization signal block groups and/or the quantity ofsynchronization signal blocks or synchronization signal block groupsassociated with one RO, and/or determined based on a quantity of randomaccess resources in a RACH resource configuration period. For example, aquantity of ROs in one RO period is 2, the quantity of synchronizationsignal blocks or downlink synchronization signal block groups associatedwith one RO is 3, and the quantity of actually transmittedsynchronization signal blocks or synchronization signal block groups is8; in this case, a required value of X is 4. In addition, X may also bea fixed value, for example, the value of X is 1, 2, 4, 8, or 16. In thisway, a quantity of remaining ROs in the system can be reduced. The valueof X may be an integer multiple or a fractional multiple of the quantityof actually transmitted synchronization signal blocks.

A quantity of RACH resources in the RACH resource configuration periodmay be related to a quantity of synchronization signal blocks orsynchronization signal block groups actually transmitted in ahalf-frame. For example, if X is 1, an association period is 1. In thiscase, the quantity of RACH resources in the RACH resource configurationperiod may be the same as or may be an integer multiple or a fractionalmultiple of the quantity of actually transmitted downlinksynchronization signal blocks or synchronization signal block groups.When one RO is associated with a plurality of synchronization signalblocks or synchronization signal block groups, the quantity of RACHresources in the RACH resource configuration period may be a fractionalmultiple of the quantity of actually transmitted downlinksynchronization signal blocks or synchronization signal block groups.When a plurality of ROs are associated with one downlink synchronizationsignal block or synchronization signal block group, the quantity of RACHresources in the RACH resource configuration period may be an integermultiple of the quantity of actually transmitted downlinksynchronization signal blocks or synchronization signal block groups.When association is performed one to one, the quantity of RACH resourcesin the RACH resource configuration period may be the same as thequantity of actually transmitted downlink synchronization signal blocksor synchronization signal block groups.

X or Y may alternatively be configured. For example, X may be some orall values selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,15, and 16, for example, may be a value in 1, 2, 4, 8, and 16. The valueof Y may also be some or all values selected from 1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, and 16, for example, may be a value in 4,8, and 16. The value of X or Y may be configured in system information(such as SIB1 or SIB2 or RMSI), or may be configured in a MAC-CE, DCI, aMIB, or RRC.

It is assumed that N is the quantity of synchronization signal blocks orsynchronization signal block groups associated with one RO, and Q is thequantity of actually transmitted or possibly transmitted synchronizationsignal blocks or synchronization signal block groups. In this case, anindex j of a synchronization signal block or synchronization signalblock group associated with an i^(th) RO is (i×N) mod Q to (i×N) modQ+N−1. If j is greater than or equal to Q, j=j mod Q. For example, N is3 and Q is 8; in this case, indexes of synchronization signal blocks orsynchronization signal block groups associated with an RO with j=5 are7, 8, and 9, and mod 8 may be 0 and mode 9 may be 1. When N=1, j=i modQ, as shown in 4c.

If quantities of ROs associated with some synchronization signal blocksor synchronization signal block groups are inconsistent because there isa remaining RO resource in a random access period, last two ROs shown inFIG. 4c are remaining ROs or redundant ROs.

In an implementation, a remaining RACH resource is considered as aninvalid RACH resource and may be not associated with any synchronizationsignal block or synchronization signal block group. In other words, theterminal device may not send any random access preamble on the randomaccess resource. A remaining RO is explained as follows: For example,one random access resource configuration period has 4 ROs, 3 periods arejointly configured, and there are 12 ROs in total. One RO is associatedwith one synchronization signal block and 5 synchronization signalblocks are associated. In this case, two remaining ROs exist, and eachRO is associated with one synchronization signal block. The 12 ROs aresorted, and indexes of the ROs are 0 to 11. ROs with indexes 0 and 5 areassociated with an SSB with an index 0. ROs with indexes 1 and 6 areassociated with an SSB with an index 1. ROs with indexes 3 and 8 areassociated with an SSB with an index 3. ROs with indexes 4 and 9 areassociated with an SSB with an index 4. ROs with indexes 10 and 11 areremaining or redundant ROs.

In another implementation, a remaining RO or a redundant RO has adifferent association relationship in every X RACH resourceconfiguration periods or random access periods. The associationrelationship may be that one or more remaining random access resourcesare associated starting from the first synchronization signal block orsynchronization signal block group, as shown in FIG. 4d . Alternatively,one or more remaining random access resources are associated startingfrom the last synchronization signal block or synchronization signalblock group, or are associated with a next synchronization signal blockof an end synchronization signal block in previous X periods, or areassociated with a next synchronization signal block group of an endsynchronization signal block group in previous X periods, as shown inFIG. 4e . For example, there are L remaining ROs in each random accessperiod, the quantity of actually transmitted synchronization signalblocks or synchronization signal block groups is Q, and M is thequantity of synchronization signal blocks or synchronization signalblock groups associated with one RO; in this case, an index j of asynchronization signal block or synchronization signal block groupassociated with an i^(th) remaining RO in a random access period with anindex m is ((m×L+i)×M) mod Q to ((m×L+i)×M) mod Q+M−1. Repeatedassociation may be sequentially performed in different random accessperiods based on the foregoing relationship, for example, starting fromthe first synchronization signal block or synchronization signal blockgroup in an odd-number period, starting from the last synchronizationsignal block or synchronization signal block group in an even-numberperiod or an odd-number period, or starting from the firstsynchronization signal block or synchronization signal block group in aneven-number period. Any one or more of the foregoing three associationrelationships may be used in different X periods.

Alternatively, the following may be implicitly or explicitly configured,including configured by the network device: “a quantity of ROs infrequency domain” and/or “a quantity of synchronization signal blocksassociated with one RO” and/or “N synchronization signal blocks or Nsynchronization signal block groups are associated with only one RO infrequency domain or are associated with all ROs in frequency domain”.The sequence includes: ROs in one RACH resource configuration period areassociated with different synchronization signal blocks orsynchronization signal block groups or a same synchronization signalblock or synchronization signal block group according to a sequence of“frequency domain first and time domain later” or “time domain first andfrequency domain later”.

The synchronization signal block or synchronization signal block groupmentioned in this application may be a synchronization signal block orsynchronization signal block group in a half-frame, and this isuniversal for all transport synchronization signal blocks.Alternatively, the synchronization signal block or synchronizationsignal block group mentioned in this application may be asynchronization signal block or synchronization signal block group inone SS/PBCH burst set.

In addition, the network device configures a quantity of synchronizationsignal blocks or synchronization signal block groups associated with oneRO as N, a quantity of actually transmitted synchronization signalblocks as Q1, a quantity of actually transmitted synchronization signalblocks in one actually transmitted synchronization signal block group asQ2, and a quantity of actually transmitted synchronization signal blockgroups as Q3, where Q1, Q2, and Q3 may be multiples of N. The terminaldevice may determine a value of N based on a factor of any one or morevalues of Q1, Q2, and Q3. For example, if Q1=6, a value range of N canonly be 1, 2, 3, and 6. P is a factor of Q1, in other words, Q1 is amultiple of N. The network device may set the value of N to some valuesof factors of any one or more values of Q1, Q2, and Q3, for example,first H values, where H may be any value of 1, 2, 3, 4, 5, 6, 7, and 8.The first H values may be first H smallest values in ascending order, ormay be first H largest values in descending order. For example, if Q1=24and H=4, only four factors 1, 2, 3, and 4 are selected. For example, thenetwork device configures the quantity of synchronization signal blocksor synchronization signal block groups associated with one RO as N, andthe value of N may be 3 or 4. When the quantity of actually transmittedsynchronization signal blocks or synchronization signal block groups is6, N is 3; when the quantity of actually transmitted synchronizationsignal blocks or synchronization signal block groups is 8, N is 4.

When the quantity of synchronization signal blocks associated with oneRO is N, and a quantity of contention-based or non-contention-based orall random access preambles in one RO is N1, a quantity N2 of randomaccess preambles associated with one SSB is no more than floor(N1/N) orN1/N. A value of N1 may be any one or more values of 4, 8, 12, 16, 20,24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 128, and 256. The terminaldevice does not desire that a quantity of random access preambles thatis configured by the network device is greater than floor(N1/N) or N1/N.Alternatively, when a quantity of random access preambles that isconfigured by the network device and that is received by the terminaldevice is greater than floor(N1/N) or N1/N, a preamble is selected fromno more than floor(N1/N) or N1/N preambles. A benefit is that differentrandom access preambles may be associated with different synchronizationsignal blocks, and the random access preambles associated with thedifferent synchronization signal blocks do not overlap each other. Inthis way, the network device can differentiate between terminal deviceswith spatial domain parameters (beams) corresponding to differentSS/PBCH blocks. The value of N may be some or all values of 1, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, and 18. The network device mayconfigure a quantity of random access preambles associated with one SSBat a granularity of 4 or 2 or 1. The granularity may be determined basedon the quantity of synchronization signal blocks associated with one RO.For example, when the quantity of synchronization signal blocksassociated with one RO is 1, the granularity is 4, or when the quantityof synchronization signal blocks associated with one RO is greater than1, the granularity is 2 or 1.

The association relationship between an RO and a quantity ofsynchronization signal blocks is determined above. After the associationrelationship between an RO and a quantity of synchronization signalblocks or synchronization signal block groups is determined, indexes ofthe RO and the synchronization signal block need to be associated. Aspecific association manner is as follows:

The association relationship between an RO and a synchronization signalblock may be configured in a one-to-many, many-to-one, one-to-one, ormany-to-many manner. When the association relationship between a randomaccess timing and a synchronization signal block is configured in themany-to-one manner, to be specific, when N random accesspreambles/timings are associated with one synchronization signal block,the N random access timings may be frequency division multiplexed, to bespecific, arranged at a same time but different frequencies; or may meettime division multiplexed, to be specific, located on different timeresources; or may be both time division multiplexed (TDM) and frequencydivision multiplexed (FDM). A value of N may be 1, 2, 4, and 6, or maybe 1, 2, 4, and 8, or may be at least one or four of 1, 2, 3, 4, 5, 6,7, 8, 9, 10, 11, 12, 13, 14, 15, and 16. The quantity of synchronizationsignal blocks associated with one random access timing may be 1, 2, or4. Alternatively, one or two synchronization signal block groups may beassociated with one random access timing. Alternatively, all frequencydivision multiplexed ROs may be associated with one synchronizationsignal block.

A quantity M of synchronization signal blocks associated with N (N>1)ROs may be at least one of 1, 2, 3, 4, 5, 6, 7, and 8, for example, maybe 1, 2, or 4. Alternatively, a quantity M of synchronization signalblock groups associated with N (N>1) ROs may be at least one of 1, 2, 3,4, 5, 6, 7, and 8, for example, may be 1 or 2.

When an association relationship of associating N ROs with Msynchronization signal blocks may be configured in the one-to-onemanner, for example, an n^(th) RO may be configured to associate with anm^(th) synchronization signal block, m may be equal to n, a value of mmay be 0 to M−1, and a value of n may be 0 to N−1. Alternatively,one-to-many, many-to-many, or one-to-one configuration may be performed.There may be five methods for one-to-many configuration.

In a first configuration method for associating M synchronization signalblocks with N ROs, the M synchronization signal blocks are associatedwith each of the N ROs. For example, if M=2 and N=2, a synchronizationsignal block with an index in {m, m+1} is associated with an RO with anindex n, and a downlink synchronization signal block with an index in{m, m+1} is associated with an RO with an index n+1, where m and n arerespectively multiples of M and N, and m may be equal to n. For example,if M=2 and N=2, a synchronization signal block with an index in {m, . .. , m+M−1} is associated with each RO with an index in {n, . . . ,n+N−1}, where m and n are respectively multiples of M and N, and m maybe equal to n. For example, a synchronization signal block with an indexi may be associated with an RO with an index j, wherefloor(i/M)=floor(j/N), i may be equal to m, and j may be equal to n.

In a second configuration method, M synchronization signal blocks areassociated with corresponding ROs in N ROs, and each RO is associatedwith a different synchronization signal block. For example, asynchronization signal block with an index i is associated with an ROwith an index j, where n=j mod N; m=i mod M; m=n×M, or (i mod M)=(j modN)×M; M may be in a relationship with N, for example, a multiplerelationship, and M may be a multiple of N obtained by multiplying N by1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. For example, a synchronization signalblock with an index in {m, . . . , m+M−1} is associated with an RO withan index n, where m=n×M, or i=j×M.

In a third configuration method for associating M synchronization signalblocks with N ROs, an RO with an index in {n, . . . , n+N−1} isassociated with each of the M synchronization signal blocks, as shown inFIG. 4b . For example, an RO with an index in {n, . . . , n+N−1} isassociated with a synchronization signal block with an index i, where iis any value in {m, . . . , m+M−1}. For example, a synchronizationsignal block with an index i is associated with an RO with an index j,where floor(i/M)=floor(j/N). For example, if M=2 and N=2, an RO with anindex in {n, n+1} is associated with a synchronization signal block withan index m, and an RO with an index in {n, n+1} is associated with asynchronization signal block with an index m, where m and n arerespectively multiples of M and N, and m may be equal to n. For example,a synchronization signal block with an index i is associated with an ROwith an index j, where floor(i/M)=floor(j/N).

In a fourth configuration method, N ROs are associated withcorresponding synchronization signal blocks, and each synchronizationsignal block is associated with a different RO. An RO with an index in{n, n+1}, {n, n+1, n+2}, {n, n+1, n+2, n+3}, or {n, n+1, n+2, n+3, n+4,n+5} is associated with a synchronization signal block with an index m,where in this case, m is an even number, n=m×2, n=m×4, n=m×3, or n=m×6.For example, an RO with an index in {n, . . . , n+N−1} is associatedwith a synchronization signal block with an index m, where n=m×N. Forexample, a synchronization signal block with an index i is associatedwith an RO with an index j, where j=i×N.

In a fifth configuration method, M synchronization signal blocks areassociated with N ROs through repeated association or puncturing(“punctured” has a same meaning as “released”, “deleted”, “unused”, “nottransmitted”, “not associated”, and “not corresponding”, or the terminaldevice does not send a random access preamble on the punctured RO): Anindex relationship of an index n of an RO associated with asynchronization signal block with an index m is: m mod M=(n mod N) modM.

Values of M and N each may be any value of 1, 2, 3, 4, 5, 6, 7, 8, 10,12, 14, and 16. The value of N may be set based on a quantity offrequency division multiplexed ROs. For example, the value of N is afactor of the quantity of frequency division multiplexed ROs or is thequantity of frequency division multiplexed ROs. The value of M may be afactor of a quantity of actually transmitted synchronization signalblocks, or may be a configured value. The value of M is related to thevalue of N. The two values may be in a multiple relationship, or onevalue may be less than the other value.

There are five configuration methods for associating a plurality of ROswith one or more synchronization signal block groups. In a firstconfiguration method for associating M synchronization signal blockgroups with N ROs, the M synchronization signal block groups areassociated with each of the N ROs. For example, if M=2 and N=2, asynchronization signal block group with an index in {m, m+1} isassociated with an RO with an index n, and a synchronization signalblock group with an index in {m, m+1} is associated with an RO with anindex n+1, where m and n are respectively multiples of M and N, and mmay be equal to n. For example, if M=2 and N=2, a synchronization signalblock group with an index in {m, . . . , m+M−1} is associated with eachRO with an index in {n, . . . , n+N−1}, where m and n are respectivelymultiples of M and N, and m may be equal to n. For example, asynchronization signal block group with an index i is associated with anRO with an index j, where floor(i/M)=floor(j/N).

In a second configuration method, M synchronization signal block groupsare associated with corresponding ROs in N ROs, and each RO isassociated with a different synchronization signal block group. Forexample, a synchronization signal block group with an index i isassociated with an RO with an index j, where n=j mod N; m=i mod M;m=n×M, or (i mod M)=(j mod N)×M; M may be in a relationship with N, forexample, a multiple relationship, and M may be a multiple of N obtainedby multiplying N by 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. For example, asynchronization signal block group with an index in {m, . . . , m+M−1}is associated with an RO with an index n, where m=n×M, or i=j×M.

In a third configuration method for associating M synchronization signalblock groups with N ROs, an RO with an index in {n, . . . , n+N−1} isassociated with each of the M synchronization signal block groups, asshown in FIG. 1. For example, an RO with an index in {n, . . . , n+N−1}is associated with a synchronization signal block group with an index i,where i is any value in {m, . . . , m+M−1}. For example, asynchronization signal block group with an index i is associated with anRO with an index j, where floor(i/M)=floor(j/N). For example, if M=2 andN=2, an RO with an index in {n, n+1} is associated with asynchronization signal block group with an index m, and an RO with anindex in {n, n+1} is associated with a synchronization signal blockgroup with an index m, where m and n are respectively multiples of M andN, and m may be equal to n. For example, a synchronization signal blockgroup with an index i is associated with an RO with an index j, wherefloor(i/M)=floor(j/N).

In a fourth configuration method, N ROs are associated withcorresponding synchronization signal block groups, and eachsynchronization signal block group is associated with a different RO. AnRO with an index in {n, n+1}, {n, n+1, n+2}, {n, n+1, n+2, n+3}, or {n,n+1, n+2, n+3, n+4, n+5} is associated with a synchronization signalblock group with an index m, where in this case, m is an even number,n=m×2, n=m×4, n=m×3, or n=m×6. For example, an RO with an index in {n, .. . , n+N−1} is associated with an RO with an index m, where n=m×N. Forexample, a synchronization signal block group with an index i isassociated with an RO with an index j, where j=i×N.

In a fifth configuration method, M synchronization signal block groupsare associated with N ROs through repeated association or puncturing(“punctured” has a same meaning as “released”, “deleted”, “unused”, “nottransmitted”, “not associated”, and “not corresponding”): An indexrelationship of an index n of an RO associated with a synchronizationsignal block group with an index m is: m mod M=(n mod N) mod M.

Values of M and N each may be any value of 1, 2, 3, 4, 5, 6, 7, 8, 10,12, 14, and 16. The network device may configure these parameters basedon any combination of the foregoing methods or by using an indexingmethod. Table 1 is a table of one configuration. Table 2 is a table ofanother configuration. The value of M may be some or all values of 1, 2,4, 6, and 8, for example, may be 1, 2, 4, and 6, or 1, 2, 4, and 8. Thevalue of N may be 1, 2, and 4. The value of N may be set based on aquantity of frequency division multiplexed ROs. For example, the valueof N is a factor of the quantity of frequency division multiplexed ROsor is the quantity of frequency division multiplexed ROs. The value of Mmay be a factor of a quantity of actually transmitted synchronizationsignal blocks, or may be a configured value. The value of M is relatedto the value of N.

It should be noted that, an index n of an RO may be an index of an RO inone association period (time period for association), or may be an indexof an RO in X RACH resource configuration periods, or may be an index ofan RO in one RACH resource configuration period, and may be collectivelyreferred to as an index of an RO in a period. The index n has aplurality of forms. A first form is a direct index n, and a value of nmay be 0, 1, 2, 3, and 4. The index n is related to an RO count in aperiod, and is unrelated to another parameter. If there are 8 ROs in aperiod, the value of the index n is 0 to 7. In a second value settingmethod, the value of n is related to an RO location, and may becalculated by using the RO location, including a frequency location anda time-domain location. For example, one indexing method is n=f(s_id,t_id, f_id, _ul_carrier_id), and another index calculation method isn=f(s_id, t_id, f_id, _ul_carrier_id) mod B, where B is a quantity ofROs in a period. f(s_id, t_id, f_id, _ul_carrier_id) indicates that n isrelated to at least one parameter in s_id, t_id, f_id, and_ul_carrier_id. For example, a calculation method is f(s_id, t_id, f_id,_ul_carrier_id)=1+s_id+14×t_id+14×X×f_id+14×X×Y×ul_carrier_id, wheres_id is a PRACH start symbol; t_id is a PRACH timeslot symbol; f_id is aPRACH frequency-domain location, and a value of f_id is greater than orequal to 0 and less than or equal to Y; ul_carrier_id is an uplinkcarrier index of a PRACH message 1; X is a maximum quantity oftime-domain RACH resources; and Y is a maximum value of afrequency-domain RACH resource. This index may also be an index of afrequency division multiplexed RO.

n may alternatively be related to a quantity of synchronization signalblocks or synchronization signal block groups in a half-frame, orrelated to a quantity of synchronization signal blocks or asynchronization signal block groups associated with one RO, or relatedto a quantity M3 of random access resources in one random accessresource configuration period or one random access resource associationperiod. For example, n=n2 mod M2, where n2 is an index of an RO in aperiod, and M2 may be the quantity of synchronization signal blocks in ahalf-frame. For example, n=n2×M1, where M1 indicates a quantity ofsynchronization signal blocks or synchronization signal block groupsassociated with one RO. In an association relationship, an index of asynchronization signal block associated with an n2^(th) RO is (n2×M1)mod M2 to (n2×(M1+1)−1) mod M2. For example, n=n2+i×M3 orn=(n2+i×M3)×M1, where i indicates an index of a random access resourceconfiguration period or a random access resource association period in arandom access period. In an association relationship, an index of asynchronization signal block associated with the n2^(th) RO is n mod M2to (n+M1−1) mod M2. K indicates a quantity of synchronization signalblocks in one synchronization signal block group. When an RO isassociated with a synchronization signal block group, an index of thesynchronization signal block group may be used to represent an index mof an SS block, or m may be used to represent k, where k=floor(m/K). gindicates a synchronization signal block group. For example, 1gindicates one group and 2g indicates two groups.

The network device may configure these parameters based on anycombination of the foregoing methods or by using an indexing method.Table 1 is a table of one configuration. Table 2 is a table of anotherconfiguration. The network device may select some or all configuredvalues or some or all rules in the tables for configuration. Example inTable 1 and Table 2 provides examples of Rule and Quantity association.The network device may perform configuration based on Rule and Quantityassociation, or Example, or Rule or Quantity association, or Version, orVersion and Example.

TABLE 1 Configuration table of an association relationship between asynchronization signal block or a synchronization signal block group andan RO Quantity Index n_(RO) n_(SSB) Rule association Version Example 0 11 m = n 1 to 1 0 Mapped to the only one FDMed RO, m = n 1 1 2 n =floor(m/2) 1 to 2 0 Mapped to the only one FDMed RO, n = floor(m/2) 2 14 n = floor(m/4) 1 to 4 0 Mapped to the only one FDMed RO, n =floor(m/4) 3 1 1 n = k 1 to 1 g 0 Mapped to the only one group FDMed RO,n = k 4 1 2 n = floor(k/2) 1 to 2 g 0 Mapped to the only one groupsFDMed RO, n = floor(k/2) 5 2 1 m = floor(n/2) 2 to 1 0 One SSB mapped toall the FDMed ROs, m = floor(n/2) 6 2 1 m = n 1 to 1 1 SSB₀ → RO₀, SSB₁→ RO₁, m = n 7 2 2 floor(m/2) = 2 to 2 0 {SSB₀, SSB₁} → RO₀, floor(n/2){SSB₀, SSB₁} → RO₁, floor(m/2) = floor(n/2) 8 2 2 n = floor(m/2) 1 to 21 {SSB₀, SSB₁} → RO₀, {SSB₂, SSB₃} → RO₁ n = floor(m/2) 9 2 4 floor(m/4)= 2 to 4 0 {SSB₀, . . . , SSB₃} → RO₀, floor(n/2) {SSB₀, . . . , SSB₃} →RO₁, floor(m/4) = floor(n/2) 10 2 1 k = floor(n/2) 2 to 1 g 0 {SSBs ingroup 0} → group or floor(m/K) = RO₀, {SSBs in group 0} floor(n/2) →RO₁, k = floor(n/2) or floor(m/K) = floor(n/2) 11 2 1 k = n or 1 to 1 g1 {SSBs in group 0} → group floor(m/K) = n RO₀, {SSBs in group 1} → RO₁,k = n or floor(m/K) = n 12 2 2 floor(k/2) = 2 to 2 g 0 {SSBs in group 0,SSBs in groups floor(n/2) or group 1} → RO₀, floor(m/(2 × floor(k/2) =floor(n/2) K)) = floor(n/2) {SSBs in group 0, SSBs in group 1} → RO₁,floor(m/(2 × K)) = floor(n/2) 13 2 2 n = floor(k/2) 1 to 2 g 1 {SSBs ingroup 0, SSBs in groups or n = group 1} → RO₀, n = floor(m/(2 ×floor(k/2) or K)) {SSBs in group 2, SSBs in group 3} → RO₁, n =floor(m/(2 × K)) 14 4 1 m = floor(n/4) 4 to 1 0 One SSB mapped to allthe FDMed ROs, m = floor(n/4) 15 4 1 m = n 1 to 1 1 SSB₀ → RO₀, SSB₁ →RO₁, SSB₂ → RO₂, SSB₃ → RO₃, m = n 16 4 2 floor(m/2) = 4 to 2 0 {SSB₀,SSB₁} → RO₀, floor(n/4) {SSB₀, SSB₁} → RO₁, {SSB₀, SSB₁} → RO₂, {SSB₀,SSB₁} → RO₃, floor(m/2) = floor(n/4) 17 4 2 floor(m/2) = n 1 to 2 1{SSB₀, SSB₁} → RO₀, mod 4 or {SSB₂, SSB₃} → RO₁, floor(m/2) = n {SSB₄,SSB₅} → RO₂, {SSB₆, SSB₇} → RO₃, floor(m/2) = n mod 4 or floor(m/2) = n18 4 4 floor(m/4) = 4 to 4 0 {SSB₀, . . . , SSB₃} → RO₀, floor(n/4){SSB₀, . . . , SSB₃} → RO₁, floor(m/4) = floor(n/4) {SSB₀, . . . , SSB₃}→ RO₂, {SSB₀, . . . , SSB₃} → RO₃ 19 4 1 k = floor(n/4) 4 to 1 g 0 {SSBsin group 0} → group RO₀, {SSBs in group 0} → RO₁, k = floor(n/4) {SSBsin group 0} → RO₂, {SSBs in group 0} → RO₃ 20 4 1 k = n 1 to 1 g 1 {SSBsin group 0} → group RO₀, {SSBs in group 1} → RO₁, k = n {SSBs in group2} → RO₂, {SSBs in group 3} → RO₃ 21 4 2 floor(n/4) = 4 to 2 g 0 {SSBsin group 0, SSBs in groups floor(k/2) group 1} → RO₀, floor(n/4) =floor(k/2) {SSBs in group 0, SSBs in group 1} → RO₁ {SSBs in group 0,SSBs in group 1} → RO₂ {SSBs in group 0, SSBs in group 1} → RO₃ 22 4 2 n= floor(k/2) 1 to 2 g 1 {SSBs in group 0, SSBs in groups or n mod 4 =group 1} → RO₀, n = floor(k/2) floor(k/2) or n mod 4 = floor(k/2) {SSBsin group 2, SSBs in group 3} → RO₁ {SSBs in group 4, SSBs in group 5} →RO₃ {SSBs in group 6, SSBs in group 7} → RO₄ 23 6 1 m = floor(n/6) 6 to1 0 One SSB mapped to all the FDMed ROs, m = floor(n/6) 24 6 1 m = n 1to 1 1 SSB₀ → RO₀, . . . , SSB₅ → RO₅, m = n 25 6 2 floor(m/2) = 6 to 20 {SSB₀, SSB₁} → RO₀, . . . , floor(n/6) {SSB₀, SSB₁} → RO₅, floor(m/2)= floor(n/6) 26 6 2 floor(m/2) = n 1 to 2 1 {SSB₀, SSB₁} → RO₀, . . . ,mod 6 or {SSB₁₀, SSB₁₁} → RO₁, floor(m/2) = n floor(m/2) = n mod 6 orfloor(m/2) = n 27 6 4 floor(m/4) = 6 to 4 0 {SSB₀, . . . , SSB₃} →floor(n/6) RO₀, . . . , {SSB₀, . . . , SSB₃} → RO₅, floor(m/4) =floor(n/6) 28 6 1 k = floor(n/6) 6 to 1 g 0 {SSBs in group 0} → groupRO₀, . . . , {SSBs in group 0} → RO₅, k = floor(n/6) 29 6 1 k = n 6 to 1g 1 {SSBs in group 0} → group RO₀, . . . , {SSBs in group 5} → RO₅, k =n 30 6 2 floor(n/6) = 6 to 2 g 0 {SSBs in group 0, SSBs in groupsfloor(k/2) group 1} → RO₀, . . . , floor(n/6) = floor(k/2) {SSBs ingroup 0, SSBs in group 1} → RO₅ 31 NA NA NA NA

TABLE 2 Configuration table of an association relationship between asynchronization signal block or a synchronization signal block group andan RO Quantity Index n_(RO) n_(SSB) Rule association Version Example 0 11 m = n 1 to 1 0 Mapped to the only one FDMed RO 1 1 2 n = floor(m/2) 1to 2 0 Mapped to the only one FDMed RO 2 1 4 n = floor(m/4) 1 to 4 0Mapped to the only one FDMed RO 3 1 All 0 Mapped to the only one FDMedRO 4 NA NA NA NA 5 2 1 m = floor(n/2) 2 to 1 0 One SSB mapped to all theFDMed ROs 6 2 1 m = n 1 to 1 1 SSB₀ → RO₀, SSB₁ → RO₁ 7 2 2 floor(m/2) =2 to 2 0 {SSB₀, SSB₁} → RO₀, floor(n/2) {SSB₀, SSB₁} → RO₁ 8 2 2 n =floor(m/2) 1 to 2 1 {SSB₀, SSB₁} → RO₀, {SSB₂, SSB₃} → RO₁ 9 2 4floor(m/4) = 2 to 4 0 {SSB₀, . . . , SSB₃} → RO₀, floor(n/2) {SSB₀, . .. , SSB₃} → RO₁ 10 2 4 k = floor(n/2) or 2 to 1 g 1 {SSB₀, . . . , SSB₃}→ RO₀, floor(m/K) = {SSB₅, . . . , SSB₇} → RO₁, floor(n/2) for >4 SSBs11 2 All k = n or 1 to 1 g 0 {SSB₀, . . . , SSB₇} → RO₀, floor(m/K) = n{SSB₀, . . . , SSB₇} → RO₁, for >4 SSBs 12 2 All floor(k/2) = 2 to 2 g 1{SSB₀, . . . , SSB₃} → RO₀, floor(n/2) or {SSB₅, . . . , SSB₇} → RO₁,floor(m/(2 × K)) = for >4 SSBs floor(n/2) 13 NA NA n = floor(k/2) or n =1 to 2 g NA NA floor(m/(2 × K)) 14 4 1 m = floor(n/4) 4 to 1 0 One SSBmapped to all the FDMed ROs 15 4 1 m = n 1 to 1 1 SSB₀ → RO₀, SSB₁ →RO₁, SSB₂ → RO₂, SSB₃ → RO₃ 16 4 2 floor(m/2) = 4 to 2 0 {SSB₀, SSB₁} →RO₀, floor(n/4) {SSB₀, SSB₁} → RO₁, {SSB₀, SSB₁} →RO₂, {SSB₀, SSB₁} →RO₃ 17 4 2 floor(m/2) = n 1 to 2 1 {SSB₀, SSB₁} → RO₀, mod 4 or {SSB₂,SSB₃} → RO₁, floor(m/2) = n {SSB₄, SSB₅} → RO₂, {SSB₆, SSB₇} → RO₃ 18 44 floor(m/4) = 4 to 4 0 {SSB₀, . . . , SSB₃} → RO₀, floor(n/4) {SSB₀, .. . , SSB₃} → RO₁ {SSB₀, . . . , SSB₃} → RO₂, {SSB₀, . . . , SSB₃} → RO₃19 4 4 k = floor(n/4) 4 to 1 g 1 {SSB₀, . . . , SSB₃} → RO₀, {SSB₄, . .. , SSB₇} → RO₁ {SSB₀, . . . , SSB₃} → RO₂, {SSB₄, . . . , SSB₇} → RO₃,for >4 SSBs 20 4 All k = n 1 to 1 g 0 {SSB₀, . . . , SSB₇} → RO₀, . . ., {SSB₀, . . . , SSB₇} → RO₃, for >4 SSBs 21 NA NA floor(n/4) = 4 to 2 gNA NA floor(k/2) 22 NA NA n = floor(k/2) or n 1 to 2 g NA NA mod 4 =floor(k/2) 23 6 1 m = floor(n/6) 6 to 1 0 One SSB mapped to all theFDMed ROs 24 6 1 m = n 1 to 1 1 SSB₀ → RO₀, . . . , SSB₃ → RO₃, SSB₀ →RO₄, SSB₁ → RO₅, for ≤4 SSBs SSB₀ → RO₀, . . . , SSB₅ → RO₅, for >4 SSBs25 6 2 floor(m/2) = 6 to 2 0 {SSB₀, SSB₁} → RO₀, . . . , floor(n/6){SSB₀, SSB₁} → RO₅ 26 6 2 floor(m/2) = n 1 to 2 1 {SSB₀, SSB₁} → RO₀, .. . , mod 6 or {SSB₄, SSB₅} → RO₂ floor(m/2) = n {SSB₀, SSB₁} → RO₃, . .. , {SSB₄, SSB₅} → RO₅, for ≤4 SSBs 27 6 4 floor(m/4) = 6 to 4 0 {SSB₀,. . . , SSB₃} → floor(n/6) RO₀, . . . , {SSB₀, . . . , SSB₃} → RO₅ 28 64 k = floor(n/6) 6 to 1 g 1 {SSB₀, . . . , SSB₃} → RO₀, {SSB₄, . . . ,SSB₇} → RO₁ {SSB₀, . . . , SSB₃} → RO₂, {SSB₄, . . . , SSB₇} → RO₃{SSB₀, . . . , SSB₃} → RO₄, {SSB₄, . . . , SSB₇} → RO₅ 29-31 Reserved

In another implementation, the network device may separately configurethe quantity of frequency division multiplexed ROs (of a same time), forexample, may configure values {F1, F2, F3, F4}. For example, F1, F2, F3,and F4 are respectively 1, 2, 4, and 6; or may be configured as 1, 2, 4,and 8; or may be 1, 2, 3, and 4; or may be some or all values of 1, 2,3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16, for example, may betwo, three, or four values thereof, for example, may be 1 and 2, or 1and 4, with remaining values reserved. The network device may alsoseparately configure the quantity N of synchronization signal blocksassociated with one RO, and may configure the value of N as 1/F, 2/F, ½,1, 2, 4, 5, 6, 7, or 8, and 1 group, 2 groups, 3 groups, 4 groups, 5groups, 6 groups, 7 groups, or 8 groups, where F is any value or afactor of any value in {F1, F2, F3, F4}.

In an implementation, if a quantity of configured frequency divisionmultiplexed ROs is F1, in this case, the quantity N of synchronizationsignal blocks (or synchronization signal block groups) associated withone RO should be a factor of F1 or an integer that is not greater thanthe quantity of actually transmitted synchronization signal blocks (orsynchronization signal block groups). The terminal device does notdesire that the base station configures another value. Alternatively, ifthe base station configures another value, the terminal device sets N toa preset value by default.

In an implementation, if a quantity of configured frequency divisionmultiplexed ROs is F2, in this case, the quantity N of synchronizationsignal blocks (or synchronization signal block groups) associated withone RO should be a factor of F2 or an integer that is not greater thanthe quantity of actually transmitted synchronization signal blocks (orsynchronization signal block groups). The terminal device does notdesire that the base station configures another value. Alternatively, ifthe base station configures another value, the terminal device sets N toa preset value by default.

In an implementation, if a quantity of configured frequency divisionmultiplexed ROs is F3, in this case, the quantity N of synchronizationsignal blocks (or synchronization signal block groups) associated withone RO should be a factor of F3 or an integer that is not greater thanthe quantity of actually transmitted synchronization signal blocks (orsynchronization signal block groups). The terminal device does notdesire that the base station configures another value. Alternatively, ifthe base station configures another value, the terminal device sets N toa preset value by default.

In an implementation, if a quantity of configured frequency divisionmultiplexed ROs is F4, in this case, the quantity N of synchronizationsignal blocks (or synchronization signal block groups) associated withone RO should be a factor of F4 or an integer that is not greater thanthe quantity of actually transmitted synchronization signal blocks (orsynchronization signal block groups). The terminal device does notdesire that the base station configures another value. Alternatively, ifthe base station configures another value, the terminal device sets N toa preset value by default.

In another implementation, the network device may specify the maximumquantity of synchronization signal blocks associated with one RO as 16or 8. The network device may configure a quantity of ROs based on both aquantity of synchronization signal blocks and a quantity ofsynchronization signal block groups. In a configuration method, thequantity of synchronization signal blocks that may be associated withone RO and the quantity of synchronization signal block groups that maybe associated with one RO each is 1/F, ½, 1, 2, 3 or 4, 1 group, 2groups, 3 or 4 groups, or all groups. The quantities may be representedby using 3 bits. The value 3 or 4 indicates that when a quantity ofactually transmitted synchronization signal blocks in one group is 3 or6, a value is set to 3; or when a quantity of actually transmittedsynchronization signal blocks or a quantity of actually transmittedsynchronization signal blocks in one group is 4 or 8, a value is set to4. In a configuration method, the quantity of synchronization signalblocks that may be associated with one RO and the quantity ofsynchronization signal block groups that may be associated with one ROare 1/F, ½, 1, 2, 3, 4, or all. The quantities may be represented byusing 3 bits. In a configuration method, the quantity of synchronizationsignal blocks that may be associated with one RO is classified into twotypes. A first type is many-to-one, which indicates that the quantity ofsynchronization signal blocks associated with one RO is a fractionalvalue, to be specific, a plurality of synchronization signal blocks areassociated with one RO. The quantity of synchronization signal blocksassociated with one RO may be 1/F, ½, and 2/F, or may be 1/F and ½, ormay be 1/F and 2/F, or may be 1/F. This part of configuration may berelated to a value of F. A second type is that one RO is associated withone or more synchronization signal blocks, and is one-to-many andone-to-one. A value configured in the one-to-many manner may be based onthe quantity of actually transmitted synchronization signal blocks or isrelated to a quantity of all synchronization signal blocks in onesynchronization signal block group. Values that may be configuredinclude 1, 2, 3, 4, 5, 6, 7, and 8, where 5, 6, and 7 may be configuredtogether with 4 or 8. When 5, 6, and 7 are configured together with 8,the quantity of synchronization signal blocks that may be associatedwith one RO is one group or All. 3 and 4 may be configured together, or3 and 4 may also be configured together with 5. In this case, the valuesthat may be configured are 1, 2, 4, and all, or 1, 2, 3, and all, or 1,2, Z, and all, where Z indicates 3 or 4, and is determined based on thequantity of actually transmitted synchronization signal blocks. Allindicates a total quantity of synchronization signal blocks andsynchronization signal block groups, or indicates the quantity of allsynchronization signal blocks in one synchronization signal block group.When one RO is associated with one or more synchronization signal blockgroups, the network device may configure one RO to associate with Ngroups, where a value of N may be 1, 2, 3, 4, 5, 6, 7, or 8. Duringconfiguration, the network device may configure N as 1 group or allgroups, or configure N as 1 or 2, or configure N as 1 or (2 or 3). Thenetwork device may configure all of the three types, or configure onlythe first two types.

The network device may alternatively jointly configure the quantity ofsynchronization signal blocks associated with one RO and a quantity ofrandom access preambles associated with one synchronization signalblock. In other words, a quantity of random access preambles associatedwith one RO is configured based on the quantity of synchronizationsignal blocks associated with one RO, as shown in Table 3, where NROindicates a quantity of ROs, NSS indicates a quantity of SSs, and NPindicates the quantity of random access preambles associated with onesynchronization signal block. Alternatively, some data in Table 3 may bejointly configured. For example, when the quantity of random accesspreambles associated with one RO is less than or equal to 4 or 1, aquantity of data bits for the quantity of random access preamblesassociated with one synchronization signal block is 4. When the quantityof synchronization signal blocks associated with one RO is greater than4 or 1, it indicates that some data bits for the quantity of randomaccess preambles associated with one synchronization signal block may beused to indicate the quantity of synchronization signal blocksassociated with one RO.

TABLE 3 Joint configuration of the quantity of random access preamblesassociated with one synchronization signal block and the quantity ofsynchronization signal blocks associated with one RO NRO-NSS 1-1 2-1F/2-1 F-1  1-2 NP 4 × 4 × 4 × 4 × 2 × (1 − 16) (1 − 16) (1 − 16) (1 −16) (1 − 16) NRO-NSS 1-4 (1-3) 1-8 (1-7, 1-6, 1-5) 1-10 1-12  1-14 NP 1− 8 1 − 6 1 − 5 1 − 4 1 − 4

According to the communications method provided in this embodiment ofthis application, a time-frequency location of a random access resourceassociated with each downlink synchronization signal is indicated, sothat the terminal device obtains, through downlink synchronization, atime-frequency location for sending an uplink random access signal, toavoid a blind attempt of the terminal device and a beam mismatch of thenetwork device occurring when the network device receives a randomaccess signal, thereby improving efficiency.

In a Long Term Evolution (long term evolution, LTE) communicationssystem, when a terminal device sends a random access signal, it is notconsidered whether a time-frequency resource for sending the randomaccess signal conflicts with a time-frequency resource for a periodic ora semi-statically or statically configured uplink signal. When theterminal device sends the periodic or the semi-statically or staticallyconfigured uplink signal, it is not considered whether thetime-frequency resource for sending the periodic or the semi-staticallyor statically configured uplink signal conflicts with the time-frequencyresource for random access. As a result, the random access signal or theperiodic or the semi-statically or statically configured uplink signalis interfered with, and signal receiving performance deteriorates.

Therefore, a problem of a time-frequency resource conflict occurringwhen the foregoing uplink signal is sent needs to be considered.

The embodiments of this application provide another communicationsmethod and apparatus, so that a terminal device sends an uplink signalbased on time-frequency resource indication information. In this way, atime-frequency resource conflict between uplink signals can be avoidedand signal receiving performance is improved.

FIG. 5 is a schematic diagram of an interaction process of anothercommunications method according to an embodiment of this application.The method may include the following steps:

S501: A network device sends first information and/or second informationto a terminal device. The terminal device receives the first informationand/or the second information sent by the network device. The firstinformation is used to instruct to send a first uplink signal on a firsttime-frequency resource; and/or the second information is used toinstruct to send a second uplink signal on a second time-frequencyresource.

S502: The network device/terminal device further performs any stepbelow:

when a third time-frequency resource in the first time-frequencyresource indicated by the first information is included in the secondtime-frequency resource indicated by the second information, theterminal device sends the first uplink signal to the network device on atime-frequency resource other than the third time-frequency resource inthe first time-frequency resource; and the network device receives thefirst uplink signal that is sent by the terminal device on thetime-frequency resource other than the third time-frequency resource inthe first time-frequency resource; or

when a fourth time-frequency resource in the second time-frequencyresource indicated by the second information is included in the firsttime-frequency resource indicated by the first information, the terminaldevice sends the second uplink signal to the network device on atime-frequency resource other than the fourth time-frequency resource inthe second time-frequency resource; and the network device receives thesecond uplink signal that is sent by the terminal device on thetime-frequency resource other than the fourth time-frequency resource inthe second time-frequency resource; or

when a third time-frequency resource in the first time-frequencyresource indicated by the first information overlaps a fourthtime-frequency resource in the second time-frequency resource indicatedby the second information, the terminal device sends the first uplinksignal to the network device on the first time-frequency resource,and/or the terminal device sends the second uplink signal to the networkdevice on the second time-frequency resource; and the network devicereceives the first uplink signal that is sent by the terminal device onthe first time-frequency resource, and/or the network device receivesthe second uplink signal that is sent by the terminal device on thesecond time-frequency resource.

In this embodiment, the first uplink signal is at least one of thefollowing: a periodic (periodic) signal, a semi-static (semi-static)signal, a semi-persistent (semi-persistent) signal, a periodic soundingreference signal (sounding reference signal, SRS), a periodicdemodulation reference signal (demodulation reference signal, DMRS), aperiodic physical uplink shared channel (physical uplink shared channel,PUSCH) signal, a periodic physical uplink control channel (physicaluplink control channel, PUCCH) signal, and a dynamic (dynamic)scheduling/configuration signal; and the second uplink signal is arandom access signal. The first uplink signal (that is, a periodic or asemi-statically or statically configured uplink signal) is usuallyconfigured by the network device. Uplink signal sending time andfrequency resource information of the first uplink signal may be or maybe not indicated by using a downlink control channel. Alternatively,some information in uplink signal sending time and frequency resourceinformation of the first uplink signal may be indicated by using adownlink control channel, and other time and frequency information isspecified in advance by using RRC signaling, a MAC CE, or a PDCCH order.The information specified in advance periodically occurs in terms oftime. The random access signal is used for uplink synchronization. Aconflict between time-frequency resources for sending the first uplinksignal and the second uplink signal should be reduced at a most extentor should not exist.

In practice, the first uplink signal usually occupies more timeresources and/or frequency (bandwidth) resources, and time and frequencylocations of the second uplink signal are cell-level configurations. Asa result, an overlap or a partial overlap of time and frequency resourcelocations between the first uplink signal and second uplink signalcannot be avoided. In some cases, changing the time and frequencylocations of the second uplink signal needs a relatively long time orrelatively high overheads. Therefore, scheduling the first uplink signalin the time and frequency locations of the second uplink signal shouldbe avoided as far as possible. If an overlap or a partial overlap cannotbe avoided, puncturing or not sending an overlapped part of one of thesignals is considered.

In this embodiment, before sending the first uplink signal and/or thesecond uplink signal, the terminal device receives the first informationand/or the second information sent by the network device. The firstinformation is used to instruct to send the first uplink signal on thefirst time-frequency resource; and/or the second information is used toinstruct to send the second uplink signal on the second time-frequencyresource. In other words, the network device indicates a time-frequencyresource for sending an uplink signal.

Specifically, S501 includes:

receiving, by the terminal device by using at least one type of thefollowing information, the first information and/or the secondinformation sent by the network device, where the at least one type ofthe following information includes: system information, radio resourcecontrol (radio resource control, RRC) signaling, a downlink controlchannel, and a MAC CE.

After the terminal device receives the first information and/or thesecond information, the following several implementations for sendingthe first uplink signal and/or the second uplink signal are includedbased on specific cases:

In one implementation, when the third time-frequency resource in thefirst time-frequency resource indicated by the first information isincluded in the second time-frequency resource indicated by the secondinformation, the terminal device sends the first uplink signal to thenetwork device on a time-frequency resource other than the thirdtime-frequency resource in the first time-frequency resource; and thenetwork device receives the first uplink signal that is sent by theterminal device on the time-frequency resource other than the thirdtime-frequency resource in the first time-frequency resource.Specifically, a conflicting time-frequency resource between the firsttime-frequency resource and the second time-frequency resource is thethird time-frequency resource. If the terminal device does not considera time-frequency resource conflict and directly sends the first uplinksignal on the first time-frequency resource, because the firsttime-frequency resource conflicts with the second time-frequencyresource used for sending the second uplink signal, signal receivingperformance may be affected when the network device receives the firstuplink signal and/or the second uplink signal. Therefore, the terminaldevice sends the first uplink signal to the network device on thetime-frequency resource other than the third time-frequency resource inthe first time-frequency resource, and the network device receives thefirst uplink signal that is sent by the terminal device on thetime-frequency resource other than the third time-frequency resource inthe first time-frequency resource. To be specific, the conflictingtime-frequency resource is punctured, no signal is transmitted on thisconflicting time-frequency resource, and rate matching is calculatedbased on an actually transmitted time-frequency resource. In this way,signal receiving performance of the first uplink signal and/or thesecond uplink signal can be improved.

In another implementation, when the fourth time-frequency resource inthe second time-frequency resource indicated by the second informationis included in the first time-frequency resource indicated by the firstinformation, the terminal device sends the second uplink signal to thenetwork device on the time-frequency resource other than the fourthtime-frequency resource in the second time-frequency resource; and thenetwork device receives the second uplink signal that is sent by theterminal device on the time-frequency resource other than the fourthtime-frequency resource in the second time-frequency resource.Specifically, a conflicting time-frequency resource between the secondtime-frequency resource and the first time-frequency resource is thefourth time-frequency resource. If the terminal device does not considera time-frequency resource conflict and directly sends the second uplinksignal on the second time-frequency resource, because the secondtime-frequency resource conflicts with the first time-frequency resourceused for sending the first uplink signal, signal receiving performancemay be affected when the network device receives the first uplink signaland/or the second uplink signal. Therefore, the terminal device sendsthe second uplink signal to the network device on the time-frequencyresource other than the fourth time-frequency resource in the secondtime-frequency resource, and the network device receives the seconduplink signal that is sent by the terminal device on the time-frequencyresource other than the fourth time-frequency resource in the secondtime-frequency resource. In this way, signal receiving performance ofthe first uplink signal and/or the second uplink signal can be improved.

In still another implementation, when the third time-frequency resourcein the first time-frequency resource indicated by the first informationoverlaps the fourth time-frequency resource in the second time-frequencyresource indicated by the second information, the terminal device sendsthe first uplink signal to the network device on the firsttime-frequency resource, and/or the terminal device sends the seconduplink signal to the network device on the second time-frequencyresource; and the network device receives the first uplink signal thatis sent by the terminal device on the first time-frequency resource,and/or the network device receives the second uplink signal that is sentby the terminal device on the second time-frequency resource.Specifically, an application scenario of this implementation is that theterminal device sends the first uplink signal and/or the second uplinksignal by using a first type of a transmission precoding type. Thetransmission precoding type includes the first type and a second type.When the transmission precoding type is the first type, the transmissionprecoding type is corresponding to a single carrier, for example,DFTs-OFDM, and for another example, a linear filtering single carrier.When the transmission precoding type is the second type, thetransmission precoding type is corresponding to a multicarrier, forexample, OFDM. When the transmission precoding type of the first type isused to send an uplink signal, a peak-to-average power ratio(peak-to-average power ratio, PAPR) increases if no uplink signal issent on a conflicting time-frequency resource. Therefore, in thisembodiment, for example, in the scenario (certainly, the scenario mayalternatively be another scenario) in which the transmission precodingtype of the first type is used to send an uplink signal, when the thirdtime-frequency resource in the first time-frequency resource indicatedby the first information overlaps the fourth time-frequency resource inthe second time-frequency resource indicated by the second information,avoiding signal interference to the first uplink signal and the seconduplink signal may be not considered, and the terminal device sends thefirst uplink signal on the first time-frequency resource and/or sendsthe second uplink signal on the second time-frequency resource. Thenetwork device receives the first uplink signal that is sent by theterminal device on the first time-frequency resource, and/or the networkdevice receives the second uplink signal that is sent by the terminaldevice on the second time-frequency resource.

It should be noted that, a same terminal device may send the firstuplink signal and the second uplink signal at a same time, or may sendeither of the first uplink signal and the second uplink signal at atime, in other words, send the first uplink signal and the second uplinksignal at different times. When there are a plurality of terminaldevices on the network and a time-frequency resource of one uplinksignal may be shared by the plurality of terminal devices, for example,a time-frequency resource of the second uplink signal is shared and is arandom access signal, in this case, the plurality of terminal devicessend different uplink signals, for example, a terminal device 1 sendsthe first uplink signal and a terminal device 2 sends the second uplinksignal. In this case, the terminal device 1 may send the first uplinksignal in a manner described in any of the foregoing embodiments, andthe terminal device 2 may send the second uplink signal in a mannerdescribed in any of the foregoing embodiments. The network devicereceives a corresponding uplink signal in a corresponding manner. To bespecific, if the terminal device 1 sends no signal on a location of thethird time-frequency resource that is overlapped with the time-frequencyresource of the first uplink signal and the time-frequency resource ofthe second uplink signal, the network device needs to perform ratematching for the location of the third time-frequency resource whenreceiving the first uplink signal from the terminal device 1. Similarly,if the terminal device 2 sends no signal on a location of the fourthtime-frequency resource that is common to the time-frequency resource ofthe second uplink signal and the time-frequency resource of the firstuplink signal, the network device needs to perform rate matching for thelocation of the fourth time-frequency resource when receiving the seconduplink signal from the terminal device 2.

Certainly, the network device may further indicate whether avoidingsignal interference to the first uplink signal and the second uplinksignal is considered and whether to send an uplink signal on aconflicting time-frequency resource. Therefore, further, the methodfurther includes:

sending, by the network device, third information to the terminaldevice; and receiving, by the terminal device, the third information,where the third information includes an uplink signal transmissionprecoding type, and the uplink signal transmission precoding typeincludes a first type and a second type; and

sending, by the terminal device, an uplink signal to the network devicebased on the first information, the second information, and the thirdinformation; and receiving, by the network device, the uplink signal.

In other words, in this implementation, the network device sends thethird information, to indicate to the terminal device a transmissionprecoding type for sending an uplink signal.

Furthermore, the network device/terminal device further executes anystep below:

when the uplink signal transmission precoding type is the first type,and/or the third time-frequency resource in the first time-frequencyresource indicated by the first information overlaps the fourthtime-frequency resource in the second time-frequency resource indicatedby the second information, the terminal device sends the first uplinksignal to the network device on the first time-frequency resource,and/or the terminal device sends the second uplink signal to the networkdevice on the second time-frequency resource; and the network devicereceives the first uplink signal that is sent by the terminal device onthe first time-frequency resource, and/or the network device receivesthe second uplink signal that is sent by the terminal device on thesecond time-frequency resource; or

when the uplink signal transmission precoding type is the second type,and the third time-frequency resource in the first time-frequencyresource indicated by the first information is included in the secondtime-frequency resource indicated by the second information, theterminal device sends the first uplink signal to the network device on atime-frequency resource other than the third time-frequency resource inthe first time-frequency resource; and the network device receives thefirst uplink signal that is sent by the terminal device on thetime-frequency resource other than the third time-frequency resource inthe first time-frequency resource; or

when the uplink signal transmission precoding type is the second type,and the fourth time-frequency resource in the second time-frequencyresource indicated by the second information is included in the firsttime-frequency resource indicated by the first information, the terminaldevice sends the second uplink signal to the network device on atime-frequency resource other than the fourth time-frequency resource inthe second time-frequency resource; and the network device receives thesecond uplink signal that is sent by the terminal device on thetime-frequency resource other than the fourth time-frequency resource inthe second time-frequency resource.

In specific implementation, if the uplink signal transmission precodingtype indicated by the network device is the first type, it is consideredthat the third time-frequency resource in the first time-frequencyresource indicated by the first information overlaps the fourthtime-frequency resource in the second time-frequency resource indicatedby the second information, the terminal device does not avoid signalinterference to the first uplink signal and the second uplink signal anddirectly sends the first uplink signal on the first time-frequencyresource and/or sends the second uplink signal on the secondtime-frequency resource. Alternatively, the terminal device may notconsider the uplink signal transmission precoding type. For example, inanother scenario in which avoiding signal interference may be notconsidered, the terminal device directly sends the first uplink signalon the first time-frequency resource and/or sends the second uplinksignal on the second time-frequency resource.

If the uplink signal transmission precoding type is the second type, theterminal device needs to consider a time-frequency resource conflict orsignal interference between the first uplink signal and the seconduplink signal. To be specific, the terminal device sends the firstuplink signal to the network device on a time-frequency resource otherthan the third time-frequency resource in the first time-frequencyresource, and the network device receives the first uplink signal thatis sent by the terminal device on the time-frequency resource other thanthe third time-frequency resource in the first time-frequency resource;and the terminal device sends the second uplink signal to the networkdevice on a time-frequency resource other than the fourth time-frequencyresource in the second time-frequency resource, and the network devicereceives the second uplink signal that is sent by the terminal device onthe time-frequency resource other than the fourth time-frequencyresource in the second time-frequency resource.

In this way, PAPR performance of transmission precoding of the firsttype is not affected, and impact on PAPR performance of transmissionprecoding of the second type is little. In addition, signal receivingperformance is improved because no uplink signal is sent on aconflicting time-frequency resource.

Alternatively, the network device may further indicate whether to sendthe first uplink signal and/or the second uplink signal on a conflictingtime-frequency resource, that is, indicate to the terminal devicewhether to perform a step in S502 or which step in S502 needs to beperformed. In specific implementation, the network device may indicate,to the terminal device in system information, an RRC message, a MAC CE,a PDCCH, a control channel for scheduling a random access response(msg2), or a random access response (RAR) carried in msg2, whether tosend the first uplink signal and/or the second uplink signal on aconflicting time-frequency resource. For example, the indication may be1-bit information, where “1” indicates that sending an uplink signal ona conflicting time-frequency resource is avoided (or “1” indicates thatsending an uplink signal on a conflicting time-frequency resource isavoided when the transmission precoding type is the second type, thatis, OFDM), and “0” indicates that sending an uplink signal on aconflicting time-frequency resource does not need to be avoided.Alternatively, conversely, “0” indicates that sending an uplink signalon a conflicting time-frequency resource is avoided (or “0” indicatesthat sending an uplink signal on a conflicting time-frequency resourceis avoided when the transmission precoding type is the second type, thatis, OFDM), and “1” indicates that sending an uplink signal on aconflicting time-frequency resource does not need to be avoided. Theforegoing system information may include system information of physicalbroadcast channel (PBCH) transmission, or system information of otherchannel transmission, or system information of user-request-basedtransmission. The RAR carried in the foregoing msg2 may be included in aMAC header or a MAC CE.

According to the communications method provided in this embodiment ofthis application, the terminal device sends an uplink signal based ontime-frequency resource indication information. In this way, atime-frequency resource conflict between uplink signals can be avoidedand signal receiving performance is improved. Specifically, the terminaldevice determines a location of a random access time-frequency resourcebased on the indication information. When sending an uplink signal, if atime-frequency resource of the uplink signal conflicts with a randomaccess time-frequency resource, the terminal does not send the uplinksignal on a time-frequency resource of the random access resource.Correspondingly, when receiving an uplink signal, the network deviceneeds to perform rate matching based on a random access resourcetime-frequency location of the uplink signal and a time-frequencyresource location of a random access resource.

In another embodiment, a current protocol supports transmission of up to4, 8, or 64 synchronization signal blocks based on different frequencybands. In an actual system, the network device possibly transmits lessthan 4, 8, or 64 synchronization signal blocks. Therefore, the prior artsupports the network device in notifying the terminal device of actuallytransmitted synchronization signal blocks, so that the terminal deviceperforms a function such as downlink data rate matching, that is, theseindicated transmitted synchronization signal blocks are staggered. Forexample, as shown in FIG. 6, in NR, a specific time location of anactually transmitted synchronization signal block is indicated by usingRMSI bit mapping (also referred to as bitmap, bitmap) information. For afrequency band greater than 6 GHz, there are up to 64 synchronizationsignal blocks in one SS burst set. The 64 synchronization signal blocksare divided into a maximum of 8 groups, and 8-bit information is used toindicate whether the synchronization signal block groups aretransmitted. Each group has a maximum of 8 synchronization signalblocks, and uses 8-bit information to indicate whether thesynchronization signal blocks are sent. A total of 8+8=16 bits ofinformation is used for indication. For a frequency band less than 6GHz, one SS burst set has a maximum of 8 synchronization signal blocksand uses 8-bit information for indication. For example, for thefrequency band greater than 6 GHz, information about actual transmissionof synchronization signal blocks of the frequency band is1101100110100011, and information about the groups of the frequency bandis 11011001, indicating that synchronization signal block groups 0, 1,3, 4, and 7 have actually transmitted synchronization signal blocks andother groups do not have actually transmitted synchronization signalblocks. Information inside a group is 10100011, indicating thatsynchronization signal blocks 0, 2, 6, and 7 inside the group aretransmitted.

Specific notification methods are as follows:

(1) Indication in System Information:

When there are 64 synchronization signal blocks, the 64 synchronizationsignal blocks are divided into 8 groups, and each group has 8synchronization signal blocks. In a specific indication, an 8-bit bitmapis used to indicate which group is transmitted, and another 8-bit bitmapis used to indicate which synchronization signal block in the group istransmitted.

When there are 8 synchronization signal blocks, an 8-bit bitmap isdirectly used to indicate which synchronization signal block istransmitted.

When there are 4 synchronization signal blocks, a 4-bit bitmap isdirectly used to indicate which synchronization signal block istransmitted.

(2) Indication in a MAC-CE and/or RRC Signaling and/or a PDCCH:

When there are 64/8/4 synchronization signal blocks, a 64/8/4-bit bitmapis directly used to indicate which synchronization signal block istransmitted.

Each synchronization signal block is associated with a specific RACHresource. For a specific association configuration method, refer torelated embodiments of the present invention. Details are not describedherein again. Based on this association, the network device may send aRACH resource pattern (pattern) of a specific conflicting ornon-conflicting resource to a connected-mode or idle-mode terminaldevice on basis of the foregoing existing synchronization signal blockindication. For the indication, a single carrier or a multicarrier maybe used to send only uplink data or any waveform is suitable.

The terminal device may determine a time-frequency resource location ofan uplink signal based on at least one of synchronization signallocation information, random access configuration information, andinformation about mapping between a synchronization signal and a randomaccess signal.

Specifically, in an implementation, an indication is performed based onan actually transmitted synchronization signal block.

The terminal device may reuse the existing indication to indicatewhether to send uplink data on a conflicting RACH resource. If anindication indicates that a synchronization signal block is transmitted,the terminal device needs to avoid a RACH resource associated with thissynchronization signal block. In this way, no additional indicationinformation is required.

In another implementation, an indication is performed based on anassociation relationship between a synchronization signal block and aRACH resource.

In the prior art, a synchronization signal block is associated with aRACH resource, and association of a plurality of synchronization signalblocks with a same RACH resource is supported. Therefore, an indicationmay be performed based on a synchronization signal block, and a sameindication may be provided for a plurality of synchronization signalblocks associated with a same RACH resource. A specific indicationmethod is described below:

In still another implementation, an indication is performed based on amaximum quantity of possibly transmitted synchronization signal blocks.

The network device may transmit 64/8/4 synchronization signal blocksbased on a frequency band. It is assumed that there are a maximum of 8synchronization signal blocks for a frequency band, and 2synchronization signal blocks are associated with a same RACH resource.Only a 4-bit instead of an 8-bit indication is required, and theindication does not depend on an actually transmitted synchronizationsignal block described above. For example, if “1001” is indicated to auser, the user cannot send uplink data on a RACH resource associatedwith synchronization signal blocks 1, 2, 7, and 8. Certainly, theindication may alternatively indicate that the user cannot send uplinkdata on a RACH resource associated with synchronization signal blocks 3,4, 5, and 6. This depends on a specific meaning of “1” or “0” of a bit.

In yet another implementation, an indication is performed based on anactually transmitted synchronization signal block.

An indication performed based on an actually transmitted synchronizationsignal block notified by the network device may further reduce aquantity of bits. For example, it is assumed that there are a maximum of8 synchronization signal blocks for a frequency band. However, accordingto an indication of the network device, only 6 of the 8 synchronizationsignal blocks (assuming that synchronization signal blocks 1, 2, 5, 6,7, and 8 are transmitted) are actually transmitted, and 2synchronization signal blocks are associated with a same RACH resource.In this case, only a 3-bit indication is required. For example, if “001”is indicated to a user, the user cannot send uplink data on a RACHresource associated with synchronization signal blocks 7 and 8.Certainly, the indication may alternatively indicate that the usercannot send uplink data on a RACH resource associated withsynchronization signal blocks 1, 2, 5, and 6. This depends on a specificmeaning of “1” or “0” of a bit. Because synchronization signal block 3and 4 are not transmitted, the indication is unrelated to thesynchronization signal blocks 3 and 4, and is associated with only theactually transmitted synchronization signal blocks 1, 2, 5, 6, 7, and 8.

In other words, an indication is performed based on a time-frequencylength of a random access resource associated with an actuallytransmitted synchronization signal block. For example, if thetime-frequency resource length of the random access resource associatedwith the actually transmitted synchronization signal block (or aquantity of random access time-frequency resources) is K, a bitmap witha length of K is used for indication, where K is an integer, forexample, K=1 to 128. In still yet another implementation, an indicationis performed based on a RACH configuration.

A RACH resource is configured by using RACH configuration information ina system message, and is repeated according to a specific period, forexample, 10/20/40/80/160 ms. Therefore, a RACH resource configured inone period may be directly indicated. For example, if RACH resources areconfigured in X time domains, an X-bit bitmap is used for an indication.Each bit indicates whether the terminal device needs to avoid a conflictwith a RACH resource in one time domain during uplink data transmission.A time length of the X time domains may be based on a random accesspreamble format and a subcarrier spacing of the random access preambleformat, where X is an integer, for example, X=1 to 1024.

For another example, there are F frequency division multiplexed randomaccess resources in X time domains, an indication may be performed basedon at least one of X and F. For example, an F-bit bitmap is indicated,to indicate that a frequency location conflict indicated in the F-bitbitmap needs to be processed for an uplink signal, where F is aninteger, for example, F=1 to 128. For another example, a Y-bit bitmap isindicated, to indicate that a time-frequency location conflict indicatedin the Y-bit bitmap needs to be processed for an uplink signal. Forexample, Y=F×X.

It should be noted that, the RACH configuration information includes aphysical random access channel (PRACH) configuration index and a randomaccess preamble subcarrier spacing field. The PRACH configuration indexand the random access preamble subcarrier spacing field jointlydetermine random access time resource information and/or a random accesspreamble subcarrier spacing. For example, the random access preamblesubcarrier spacing field has a length of 1 bit. When a frequency bandfor random access is a first frequency band (for example, less than 6GHz), time information is determined based on the PRACH configurationindex, the random access preamble subcarrier spacing field, and a presetfirst random access configuration table. If the random access preambleformat includes information about the random access preamble subcarrierspacing, the random access preamble subcarrier spacing field may furtherbe used to indicate time information of a random access resource. Forexample, when the random access preamble format is preamble formats 0 to3, a first time is indicated if the random access preamble subcarrierspacing field is 0, and a second time is indicated if the random accesspreamble subcarrier spacing field is 1. For example, as shown in Table3, a preamble format F may be preamble formats 0 to 3 defined in 5G, andthe random access preamble subcarrier spacing may be determined based ona value of this format. P may be understood as a random accessconfiguration period or a random access resource period, and a value ofP may be represented by using millisecond. For example, P is any one of1 ms, 5 ms, 10 ms, 20 ms, 40 ms, 80 ms, 160 ms, 320 ms, and 640 ms,where ms indicates a time unit millisecond. Alternatively, a value of Pmay be represented by using a quantity of frames, for example, 0.5, 1,2, 4, 8, 16, 32, 64, 128, or 256 frames, where each frame is 10 ms. Qindicates a time location (for example, a frame or a subframe) in whichthe random access resource appears in one period (for example, a randomaccess configuration period P). For example, when P is greater than 1, Qmay be 0 to P−1. A subframe index is a time location in which a frameappears in one period. A length of one subframe is 1 millisecond, and astart symbol may be any value from 0 to 13.

TABLE 4 Random access configuration table (first frequency band) Randomaccess Preamble Subframe Start OFDM configuration index format x y indexsymbol I F P Q N S

In Table 4, n_(SFN) mod x=y.

For example, when a random access preamble format specified by a randomaccess configuration index is preamble formats 0 to 3, it indicates thatthe random access configuration period P is a first time value if therandom access preamble subcarrier spacing field is 0, and it indicatesthat the random access configuration period P is a second time value ifthe random access preamble subcarrier spacing field is 1.

For another example, when a random access preamble format specified by arandom access configuration index is preamble formats 0 to 3, itindicates that Q is a first time value if the random access preamblesubcarrier spacing field is 0, and it indicates that Q is a second timevalue if the random access preamble subcarrier spacing field is 1.

For another example, when a random access preamble format specified by arandom access configuration index is preamble formats 0 to 3, itindicates that N is a first time value if the random access preamblesubcarrier spacing field is 0, and it indicates that N is a second timevalue if the random access preamble subcarrier spacing field is 1.

For another example, when a random access preamble format specified by arandom access configuration index is preamble formats 0 to 3, itindicates that S is a first time value if the random access preamblesubcarrier spacing field is 0, and it indicates that S is a second timevalue if the random access preamble subcarrier spacing field is 1.

FIG. 7 is a schematic structural diagram of a communications apparatus700 according to an embodiment of this application. The apparatus 700may include a receiving unit 71 and a processing unit 72.

The receiving unit 71 is configured to obtain downlink synchronizationsignal block index information, for example, receive a downlink signal,where the downlink signal carries the synchronization signal block indexinformation.

The receiving unit 71 is further configured to receive information usedto indicate an association relationship between a random access occasionRO and a synchronization signal block.

The processing unit 72 is configured to obtain the synchronizationsignal block index information and the association relationship betweena random access occasion RO and a synchronization signal block from theinformation received by the receiving unit 71, and access a networkdevice on an RO corresponding to the synchronization signal block indexinformation.

The association relationship between an RO and a synchronization signalblock is at least one of the following:

a quantity of synchronization signal blocks associated with one RO is atleast 1/F, or is P at most, where F is a quantity of ROs in frequencydomain, and P is related to a quantity of actually transmittedsynchronization signal blocks; and/or

N synchronization signal blocks or N synchronization signal block groupsare associated with one RO in frequency domain or are associated withall ROs in frequency domain; and/or

the first RACH resources in every X RACH resource configuration periodsY are associated with same synchronization signal blocks when one randomaccess resource configuration period is P, where P and X are integersand Y is equal to P multiplied by X.

In an implementation, when the association relationship is that Nsynchronization signal blocks or N synchronization signal block groupsare associated with one RO in frequency domain or are associated withall ROs in frequency domain, the receiving unit 71 is further configuredto receive indication information from the network device, where theindication information is used to indicate that the N synchronizationsignal blocks or the N synchronization signal block groups areassociated with one RO in frequency domain, or is used to indicate thatthe N synchronization signal blocks or the N synchronization signalblock groups are associated with all the ROs in frequency domain.

In another implementation, when one random access resource configurationperiod is P, and the first RACH resources in every X RACH resourceconfiguration periods are associated with same synchronization signalblocks, X is received from the network device or is prestored; and/or Yis received from the network device or is prestored.

In still another implementation, a value of Y is 10 ms, 20 ms, 40 ms, 80ms, 160 ms, 320 ms, or 640 ms.

In yet another implementation, a value of X is related to a quantity ofsynchronization signal blocks, or a value of X is related to a quantityof random access resources in one random access resource configurationperiod, or a value of X is 1, 2, 4, 8, or 16.

In still yet another implementation, when one random access resourceconfiguration period is P, and the first random access resources inevery X random access resource configuration periods are associated withsame synchronization signal blocks, if there are one or more remainingrandom access resources, the communications apparatus does not accessthe network device on the remaining random access resource.

In a further implementation, when one random access resourceconfiguration period is P, and the first random access resources inevery X random access resource configuration periods are associated withsame synchronization signal blocks, if there are one or more remainingrandom access resources, the one or more remaining random accessresources are associated starting from the first synchronization signalblock or the last synchronization signal block or a next synchronizationsignal block of an end synchronization signal block in previous Xperiods, or any one or more of the foregoing three associationrelationships are used in different X periods.

In a still further implementation, when the association relationship isthat N synchronization signal blocks or N synchronization signal blockgroups are associated with one RO in frequency domain or are associatedwith all ROs in frequency domain, if a quantity N of actuallytransmitted synchronization signal blocks or synchronization signalblock groups cannot be exactly divided by a quantity, configured by thenetwork device, of synchronization signal blocks associated with one RO,after a quantity of synchronization signal blocks or synchronizationsignal block groups are associated with a corresponding RO, where thequantity is an integer multiple of the quantity configured by thenetwork device, a remaining synchronization signal block orsynchronization signal block group is associated with another one ormore ROs.

According to the communications apparatus provided in this embodiment ofthis application, a time-frequency location of a random access resourceassociated with each downlink synchronization signal is indicated, sothat a terminal device obtains, through downlink synchronization, atime-frequency location for sending an uplink random access signal, toavoid a blind attempt of the terminal device and a beam mismatch of thenetwork device occurring when the network device receives a randomaccess signal, thereby improving efficiency.

FIG. 8 is a schematic structural diagram of another communicationsapparatus according to an embodiment of this application. The apparatus800 may include a sending unit 81 and a receiving unit 82.

The sending unit 81 is configured to send downlink synchronizationsignal block index information to a terminal device, for example, thesending unit 81 sends a downlink synchronization signal block, where thesynchronization signal block carries synchronization signal block indexinformation.

The sending unit 81 is further configured to send information used toindicate an association relationship between a random access resource ROand a synchronization signal block to the terminal device. The sendingunit is further configured to send random access channel RACHconfiguration information to the terminal device. For details, refer todescriptions in the foregoing embodiments.

The receiving unit 82 is configured to receive a random access signalthat is sent by the terminal device on an RO corresponding to thesynchronization signal block index information.

According to the communications apparatus provided in this embodiment ofthis application, a time-frequency location of a random access resourceassociated with each downlink synchronization signal is indicated, sothat the terminal device obtains, through downlink synchronization, atime-frequency location for sending an uplink random access signal, toavoid a blind attempt of the terminal device and a beam mismatch of anetwork device occurring when the network device receives a randomaccess signal, thereby improving efficiency.

FIG. 9 is a schematic structural diagram of still another communicationsapparatus according to an embodiment of this application. The apparatus900 may include a receiving unit 91 and a sending unit 92.

The receiving unit 91 is configured to receive first information and/orsecond information sent by a network device, where the first informationis used to instruct to send a first uplink signal on a firsttime-frequency resource; and/or the second information is used toinstruct to send a second uplink signal on a second time-frequencyresource.

The sending unit 92 is configured to: when a third time-frequencyresource in the first time-frequency resource indicated by the firstinformation is included in the second time-frequency resource indicatedby the second information, send the first uplink signal to the networkdevice on a time-frequency resource other than the third time-frequencyresource in the first time-frequency resource; or

further configured to: when a fourth time-frequency resource in thesecond time-frequency resource indicated by the second information isincluded in the first time-frequency resource indicated by the firstinformation, send the second uplink signal to the network device on atime-frequency resource other than the fourth time-frequency resource inthe second time-frequency resource; or

further configured to: when a third time-frequency resource in the firsttime-frequency resource indicated by the first information overlaps afourth time-frequency resource in the second time-frequency resourceindicated by the second information, send the first uplink signal to thenetwork device on the first time-frequency resource, and/or send thesecond uplink signal to the network device on the second time-frequencyresource.

In an implementation, the first uplink signal is at least one of thefollowing: a periodic signal, a semi-static signal, a semi-persistentsignal, a periodic sounding reference signal, a periodic demodulationreference signal, a periodic physical uplink shared channel signal, aperiodic physical uplink control channel signal, and a dynamicscheduling/configuration signal; and the second uplink signal is arandom access signal.

In another implementation, the receiving unit 91 is specificallyconfigured to receive, by using at least one type of the followinginformation, the first information and/or the second information sent bythe network device, where the at least one type of the followinginformation includes: system information, radio resource controlsignaling, a downlink control channel, and a Media Access Controlcontrol element MAC CE.

In still another implementation, the receiving unit 91 is furtherconfigured to receive third information, where the third informationincludes an uplink signal transmission precoding type, and the uplinksignal transmission precoding type includes a first type and a secondtype; and the sending unit 92 is further configured to send an uplinksignal to the network device based on the first information, the secondinformation, and the third information.

In yet another implementation:

when the uplink signal transmission precoding type is the first type,and/or the third time-frequency resource in the first time-frequencyresource indicated by the first information overlaps the fourthtime-frequency resource in the second time-frequency resource indicatedby the second information, the sending unit 92 is further configured tosend the first uplink signal to the network device on the firsttime-frequency resource, and/or the sending unit 92 is furtherconfigured to send the second uplink signal to the network device on thesecond time-frequency resource; or

when the uplink signal transmission precoding type is the second type,and the third time-frequency resource in the first time-frequencyresource indicated by the first information is included in the secondtime-frequency resource indicated by the second information, the sendingunit 92 is further configured to send the first uplink signal to thenetwork device on a time-frequency resource other than the thirdtime-frequency resource in the first time-frequency resource; or

when the uplink signal transmission precoding type is the second type,and the fourth time-frequency resource in the second time-frequencyresource indicated by the second information is included in the firsttime-frequency resource indicated by the first information, the sendingunit 92 is further configured to send the second uplink signal to thenetwork device on a time-frequency resource other than the fourthtime-frequency resource in the second time-frequency resource.

According to the communications apparatus provided in this embodiment ofthis application, a terminal device sends an uplink signal based ontime-frequency resource indication information. In this way, atime-frequency resource conflict between uplink signals can be avoidedand signal receiving performance is improved.

FIG. 10 is a schematic structural diagram of yet another communicationsapparatus according to an embodiment of this application. The apparatus1000 may include a sending unit 101 and a receiving unit 102.

The sending unit 101 is configured to send first information and/orsecond information to a terminal device, where the first information isused to instruct to send a first uplink signal on a first time-frequencyresource; and/or the second information is used to instruct to send asecond uplink signal on a second time-frequency resource; and

when a third time-frequency resource in the first time-frequencyresource indicated by the first information is included in the secondtime-frequency resource indicated by the second information, thereceiving unit 102 is configured to receive the first uplink signal thatis sent by the terminal device on a time-frequency resource other thanthe third time-frequency resource in the first time-frequency resource;or when a fourth time-frequency resource in the second time-frequencyresource indicated by the second information is included in the firsttime-frequency resource indicated by the first information, thereceiving unit 102 is configured to receive the second uplink signalthat is sent by the terminal device on a time-frequency resource otherthan the fourth time-frequency resource in the second time-frequencyresource; or when a third time-frequency resource in the firsttime-frequency resource indicated by the first information overlaps afourth time-frequency resource in the second time-frequency resourceindicated by the second information, the receiving unit 102 isconfigured to receive the first uplink signal that is sent by theterminal device on the first time-frequency resource, and/or thereceiving unit 102 is configured to receive the second uplink signalthat is sent by the terminal device on the second time-frequencyresource. In this aspect, the terminal device sends an uplink signalbased on time-frequency resource indication information. In this way, atime-frequency resource conflict between uplink signals can be avoidedand signal receiving performance of a network device is improved.

In a possible implementation, the sending unit 101 is further configuredto send third information to the terminal device, where the thirdinformation includes an uplink signal transmission precoding type, andthe uplink signal transmission precoding type includes a first type anda second type; and the receiving unit 102 is further configured toreceive an uplink signal that is sent by the terminal device based onthe first information, the second information, and the thirdinformation.

In another possible implementation, when the uplink signal transmissionprecoding type is the first type, and/or the third time-frequencyresource in the first time-frequency resource indicated by the firstinformation overlaps the fourth time-frequency resource in the secondtime-frequency resource indicated by the second information, thereceiving unit 102 is configured to receive the first uplink signal thatis sent by the terminal device on the first time-frequency resource,and/or the receiving unit 102 is configured to receive the second uplinksignal that is sent by the terminal device on the second time-frequencyresource; or when the uplink signal transmission precoding type is thesecond type, and the third time-frequency resource in the firsttime-frequency resource indicated by the first information is includedin the second time-frequency resource indicated by the secondinformation, the receiving unit 102 is configured to receive the firstuplink signal that is sent by the terminal device on a time-frequencyresource other than the third time-frequency resource in the firsttime-frequency resource; or when the uplink signal transmissionprecoding type is the second type, and the fourth time-frequencyresource in the second time-frequency resource indicated by the secondinformation is included in the first time-frequency resource indicatedby the first information, the receiving unit 102 is configured toreceive the second uplink signal that is sent by the terminal device ona time-frequency resource other than the fourth time-frequency resourcein the second time-frequency resource.

According to the communications apparatus provided in this embodiment ofthis application, the terminal device sends an uplink signal based ontime-frequency resource indication information. In this way, atime-frequency resource conflict between uplink signals can be avoidedand signal receiving performance of the network device is improved.

The communications apparatus provided in FIG. 7 is corresponding to themethod embodiment in FIG. 3. The communications apparatus provided inFIG. 9 is corresponding to the method embodiment in FIG. 5. Alldescriptions of the method embodiments are applicable to thecommunications apparatuses.

The communications apparatuses in FIG. 3 and FIG. 5 of this applicationeach may be a terminal device, or a chip or an integrated circuitmounted in a terminal device.

That the communications apparatus is a terminal device is used as anexample. FIG. 11 is a schematic structural diagram of a simplifiedterminal device. For ease of understanding and illustration, in FIG. 11,that the terminal device is a mobile phone is used as an example. Asshown in FIG. 11, the terminal device includes a processor, a memory, aradio frequency circuit, an antenna, and an input/output apparatus. Theprocessor is mainly configured to: process a communication protocol andcommunication data, control the terminal device, execute a softwareprogram, process data of the software program, and the like. The memoryis mainly configured to store the software program and data. The radiofrequency circuit is mainly configured to: perform conversion between abaseband signal and a radio frequency signal, and process the radiofrequency signal. The antenna is mainly configured to receive and sendradio frequency signals in a form of an electromagnetic wave. Theinput/output apparatus, such as a touchscreen, a display, or a keyboard,is mainly configured to: receive data entered by a user and output datato the user. It should be noted that terminal devices of some types maynot have the input/output apparatus.

When data needs to be sent, after performing baseband processing on thedata to be sent, the processor outputs a baseband signal to the radiofrequency circuit. The radio frequency circuit performs radio frequencyprocessing on the baseband signal and sends a radio frequency signal tooutside in a form of an electromagnetic wave by using the antenna. Whendata is sent to the terminal device, the radio frequency circuitreceives a radio frequency signal by using the antenna, converts theradio frequency signal into a baseband signal, and outputs the basebandsignal to the processor, and the processor converts the baseband signalinto data and processes the data. For ease of description, FIG. 11 showsonly one memory and processor. In an actual terminal device product,there may be one or more processors and one or more memories. The memorymay also be referred to as a storage medium, a storage device, or thelike. The memory may be disposed independent of the processor, or may beintegrated with the processor. This is not limited in this embodiment ofthis application.

In this embodiment of this application, the antenna and the radiofrequency circuit that have a receiving and sending function may beconsidered as a receiving unit and a sending unit of the terminal device(or may be collectively referred to as a transceiver unit), and theprocessor having a processing function may be considered as a processingunit of the terminal device. As shown in FIG. 11, the terminal deviceincludes a receiving unit 111, a processing unit 112, and a sending unit113. The receiving unit 111 may also be referred to as a receiver, areceiver machine, a receiver circuit, or the like. The sending unit 113may also be referred to as a sender, a transmitter, a transmittermachine, a transmitter circuit, or the like. The processing unit mayalso be referred to as a processor, a processing board, a processingmodule, a processing apparatus, or the like.

For example, in an embodiment, the receiving unit 111 is configured toperform S301 and S302 in the embodiment shown in FIG. 3. The processingunit 112 is configured to perform S303 in the embodiment shown in FIG.3.

For example, in another embodiment, the receiving unit 111 is configuredto perform S501 in the embodiment shown in FIG. 5. The sending unit 113is configured to perform S502 in the embodiment shown in FIG. 5.

An embodiment of this application further provides a communicationsapparatus. The communications apparatus is configured to perform theforegoing communications method. The foregoing communications method maybe completely or partially implemented by hardware or software. Whenhardware is used for implementation, in an embodiment, thecommunications apparatus includes: a receiver, configured to obtaindownlink synchronization signal block index information, and furtherconfigured to receive information used to indicate an associationrelationship between a random access occasion RO and a synchronizationsignal block; and a transmitter, configured to access a network deviceon an RO corresponding to the synchronization signal block indexinformation. In another embodiment, the communications apparatusincludes: a receiver, configured to receive first information and/orsecond information sent by a network device, where the first informationis used to instruct to send a first uplink signal on a firsttime-frequency resource, and/or the second information is used toinstruct to send a second uplink signal on a second time-frequencyresource; and a transmitter, configured to: when a third time-frequencyresource in the first time-frequency resource indicated by the firstinformation is included in the second time-frequency resource indicatedby the second information, send the first uplink signal to the networkdevice on a time-frequency resource other than the third time-frequencyresource in the first time-frequency resource; or further configured to:when a fourth time-frequency resource in the second time-frequencyresource indicated by the second information is included in the firsttime-frequency resource indicated by the first information, send thesecond uplink signal to the network device on a time-frequency resourceother than the fourth time-frequency resource in the secondtime-frequency resource; or further configured to: when a thirdtime-frequency resource in the first time-frequency resource indicatedby the first information overlaps a fourth time-frequency resource inthe second time-frequency resource indicated by the second information,send the first uplink signal to the network device on the firsttime-frequency resource, and/or send the second uplink signal to thenetwork device on the second time-frequency resource.

Optionally, in specific implementation, the communications apparatus maybe a chip or an integrated circuit.

Optionally, when the communications method in the foregoing embodimentis completely or partially implemented by software, the communicationsapparatus includes: a memory, configured to store a program; and aprocessor, configured to execute the program stored by the memory. Whenthe program is executed, the communications apparatus is enabled toimplement the communications method provided in the foregoingembodiment.

Optionally, the memory may be a physically independent unit, or may beintegrated with the processor.

Optionally, when the communications method in the foregoing embodimentis completely or partially implemented by software, the communicationsapparatus may include only a processor. A memory configured to store aprogram is located outside the communications apparatus. The processoris connected to the memory through a circuit/wire, and is configured toread and execute the program stored in the memory.

The processor may be a central processing unit (CPU), a networkprocessor (NP), or a combination of a CPU and an NP.

The processor may further include a hardware chip. The foregoinghardware chip may be an application-specific integrated circuit (ASIC),a programmable logic device (PLD), or a combination thereof. Theforegoing PLD may be a complex programmable logic device (CPLD), afield-programmable gate array (FPGA), a generic array logic (GAL), orany combination thereof.

The memory may include a volatile memory, for example, a random accessmemory (RAM). The memory may also include a non-volatile memory, forexample, a flash memory, a hard disk drive (HDD), or a solid-state drive(SSD). The memory may further include a combination of the foregoingtypes of memories.

The communications apparatus provided in FIG. 8 is corresponding to themethod embodiment in FIG. 3. The communications apparatus provided inFIG. 10 is corresponding to the method embodiment in FIG. 5. Alldescriptions of the method embodiments are applicable to thecommunications apparatuses.

The communications apparatus in this application may be a networkdevice, or a chip or an integrated circuit installed in a networkdevice.

That the communications apparatus is a network device is used as anexample. FIG. 12 is a schematic structural diagram of a simplifiednetwork device. The network device includes a radio frequency signalreceiving and sending and conversion part and a 122 part, and the radiofrequency signal receiving and sending and conversion part furtherincludes a receiving unit 121 part and a sending unit 123 part (whichare also collectively referred to as a transceiver unit). The radiofrequency signal receiving and sending and conversion part is mainlyconfigured to: perform radio frequency signal receiving and sending andperform conversion between a radio frequency signal and a basebandsignal. The 122 part is mainly configured to: perform basebandprocessing, control the network device, and the like. The receiving unit121 may also be referred to as a receiver, a receiver machine, areceiver circuit, or the like. The sending unit 123 may also be referredto as a sender, a transmitter, a transmitter machine, a transmittercircuit, or the like. The 122 part is usually a control center of thenetwork device, or may be usually referred to as a processing unit,configured to control the network device to perform the steps performedby the network device in FIG. 3 or FIG. 5. For details, refer todescriptions of the related parts.

The 122 part may include one or more boards. Each board may include oneor more processors and one or more memories, and the processor isconfigured to read and execute a program in the memory, to implement abaseband processing function and control the network device. If thereare a plurality of boards, the boards may be interconnected to enhance aprocessing capability. In an optional implementation, alternatively, theplurality of boards may share one or more processors, or the pluralityof boards share one or more memories, or the plurality of boards shareone or more processors at the same time.

For example, in an embodiment, the sending unit 123 is configured toperform steps S301 and S302 in the embodiment shown in FIG. 3. Thereceiving unit 121 is configured to perform step S303 in the embodimentshown in FIG. 3.

For example, in another embodiment, the sending unit 123 is configuredto perform step S501 in the embodiment shown in FIG. 5. The receivingunit 121 is configured to perform step S302 in the embodiment shown inFIG. 5.

An embodiment of this application further provides a communicationsapparatus. The communications apparatus is configured to perform theforegoing communications method. The foregoing communications method maybe completely or partially implemented by hardware or software. Whenhardware is used for implementation, in an embodiment, thecommunications apparatus includes: a transmitter, configured to senddownlink synchronization signal block index information to a terminaldevice, and further configured to send information used to indicate anassociation relationship between a random access resource RO and asynchronization signal block; and a receiver, configured to receive arandom access signal that is sent by the terminal device on an ROcorresponding to the synchronization signal block index information. Inanother embodiment, the communications apparatus includes: atransmitter, configured to send first information and/or secondinformation to a terminal device; and a receiver, configured to: when athird time-frequency resource in a first time-frequency resourceindicated by the first information is included in a secondtime-frequency resource indicated by the second information, receive afirst uplink signal that is sent by the terminal device on atime-frequency resource other than the third time-frequency resource inthe first time-frequency resource; or when a fourth time-frequencyresource in a second time-frequency resource indicated by the secondinformation is included in a first time-frequency resource indicated bythe first information, receive a second uplink signal that is sent bythe terminal device on a time-frequency resource other than the fourthtime-frequency resource in the second time-frequency resource; or when athird time-frequency resource in a first time-frequency resourceindicated by the first information overlaps a fourth time-frequencyresource in a second time-frequency resource indicated by the secondinformation, receive a first uplink signal that is sent by the terminaldevice on the first time-frequency resource, and/or receive a seconduplink signal that is sent by the terminal device on the secondtime-frequency resource.

Optionally, in specific implementation, the communications apparatus maybe a chip or an integrated circuit.

Optionally, when the communications method in the foregoing embodimentis completely or partially implemented by software, the communicationsapparatus includes: a memory, configured to store a program; and aprocessor, configured to execute the program stored by the memory. Whenthe program is executed, the communications apparatus is enabled toimplement the communications method provided in the foregoingembodiment.

Optionally, the memory may be a physically independent unit, or may beintegrated with the processor.

Optionally, when the communications method in the foregoing embodimentis completely or partially implemented by software, the communicationsapparatus may include only a processor. A memory configured to store aprogram is located outside the communications apparatus. The processoris connected to the memory through a circuit/wire, and is configured toread and execute the program stored in the memory.

The processor may be a CPU, an NP, or a combination of a CPU and an NP.

The processor may further include a hardware chip. The hardware chip maybe an ASIC, a PLD, or a combination thereof. The PLD may be a CPLD, anFPGA, a GAL, or any combination thereof.

The memory may include a volatile memory, such as a RAM. Alternatively,the memory may include a non-volatile memory, such as a flash memory, ahard disk drive, or a solid state drive. Alternatively, the memory mayinclude a combination of the foregoing types of memories.

A person of ordinary skill in the art may be aware that, the units andalgorithm steps in the examples described with reference to theembodiments disclosed in this specification may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraint conditions ofthe technical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of this application.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the system, apparatus, and unit, refer to a correspondingprocess in the method embodiments. Details are not described hereinagain.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented by using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electronic, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of theembodiments.

In addition, functional units in the embodiments of this application maybe integrated into one processing unit, or each of the units may existalone physically, or two or more units may be integrated into one unit.

All or some of the foregoing embodiments may be implemented by software,hardware, firmware, or any combination thereof. When software is used toimplement the embodiments, the embodiments may be implemented completelyor partially in a form of a computer program product. The computerprogram product includes one or more computer instructions. When thecomputer program instructions are loaded and executed on the computer,the procedure or functions according to the embodiments of thisapplication are all or partially generated. The computer may be ageneral-purpose computer, a dedicated computer, a computer network, orother programmable apparatuses. The computer instructions may be storedin a computer-readable storage medium, or may be transmitted by usingthe computer-readable storage medium. The computer instruction may betransmitted from a website, computer, server, or data center to anotherwebsite, computer, server, or data center in a wired (for example, acoaxial cable, an optical fiber, or a digital subscriber line (DSL)) orwireless (for example, infrared, radio, or microwave) manner. Thecomputer-readable storage medium may be any usable medium accessible bya computer, or a data storage device, such as a server or a data center,integrating one or more usable media. The usable medium may be amagnetic medium (for example, a floppy disk, a hard disk, or a magnetictape), an optical medium (for example, a digital versatile disc (DVD)),a semiconductor medium (for example, a solid state drive (SSD)), or thelike.

A person of ordinary skill in the art may understand that all or some ofthe processes of the methods in the embodiments may be implemented by acomputer program instructing related hardware. The program may be storedin a computer readable storage medium. When being executed, the programmay include the procedures of the foregoing method embodiments. Theforegoing storage medium includes: any medium that can store programcode, such as a read-only memory (ROM), a random access memory (RAM), amagnetic disk, or an optical disc.

What is claimed is:
 1. A communications apparatus, comprising: one ormore non-transitory memories configured to store instructions; and oneor more processors coupled to the one or more non-transitory memoriesand configured to execute the instructions to cause the apparatus to:receive at least one synchronization signal block, information used toindicate a mapping relationship between a respective synchronizationsignal block and a random access occasion, and random access channel(RACH) configuration information; and determine a random accessassociation period Y based on the information received by the apparatus,wherein the random access association period Y comprises X random accessconfiguration periods P, and a value of X is any one of 2, 4, 8, or 16,wherein the random access configuration periods are time intervals atwhich random access resources repeatedly occur, and wherein the randomaccess association period is a time in which a quantity of the randomaccess resources are associated with the respective synchronizationsignal block.
 2. The apparatus according to claim 1, wherein the valueof X is related to a quantity of the at least one synchronization signalblock.
 3. The apparatus according to claim 1, wherein the value of X isrelated to a quantity of random access occasions comprised in one randomaccess configuration period P.
 4. The apparatus according to claim 1,wherein a value of the random access association period Y is 10 ms, 20ms, 40 ms, 80 ms, 160 ms, 320 ms, or 640 ms.
 5. The apparatus accordingto claim 1, wherein any remaining random access occasions in the randomaccess association period Y are not used for accessing a network device.6. The apparatus according to claim 1, wherein any remaining randomaccess occasions in the random access association period Y are notassociated with any synchronization signal block or any synchronizationsignal block group.
 7. The apparatus according to claim 1, wherein aquantity of random access occasions in one random access configurationperiod P is 1, 2, 4, or
 8. 8. The apparatus according to claim 1,wherein the RACH configuration information comprises a physical randomaccess channel configuration index (PRACH) configuration index and arandom access preamble subcarrier spacing.
 9. The apparatus according toclaim 8, wherein the PRACH configuration index indicates one or more of:a preamble format, a random access configuration period, a frame inwhich a random access resource is located, a subframe index, or a startorthogonal frequency division multiplexing (OFDM) symbol.
 10. Theapparatus according to claim 1, wherein a maximum quantity ofsynchronization signal blocks mapped to one random access occasion is 8or
 16. 11. The apparatus according to claim 1, wherein when a quantityof synchronization signal blocks associated with one random accessoccasion is N, and a quantity of contention-based ornon-contention-based or all random access preambles in one random accessoccasion is N1, a quantity N2 of random access preambles mapped to onesynchronization signal block is no more than floor(N1/N) or N1/N,wherein floor indicates rounding down to a nearest integer; wherein avalue of N1 is any one or more values of 4, 8, 12, 16, 20, 24, 28, 32,36, 40, 44, 48, 52, 56, 60, 64, 128, or
 256. 12. The apparatus accordingto claim 1, wherein the one or more processors are further configured toexecute the instructions to cause the apparatus to: determine agranularity of a quantity of random access preambles based on a quantityof synchronization signal blocks mapped to one random access occasion,wherein the random access preambles are used to access a network device.13. The apparatus according to claim 1, wherein in one random accessassociation period Y, synchronization signal blocks or synchronizationsignal block groups are cyclically mapped to random access occasions.14. The apparatus according to claim 1, wherein in different randomaccess association periods Y, a first random access occasion is mappedto a first synchronization signal block.
 15. The apparatus according toclaim 1, wherein the value of X is
 1. 16. A communications method,comprising: receiving, by a terminal, at least one synchronizationsignal block, information used to indicate a mapping relationshipbetween a respective synchronization signal block and a random accessoccasion, and random access channel (RACH) configuration information;and determining, by the terminal, a random access association period Ybased on the information received by the terminal, the random accessassociation period Y comprising X random access configuration periods P,and a value of X being any one of 2, 4, 8, or 16, the random accessconfiguration periods being time intervals at which random accessresources repeatedly occur, and the random access association periodbeing a time in which a quantity of the random access resources areassociated with the respective synchronization signal block.
 17. Themethod according to claim 16, wherein the value of X is related to aquantity of the at least one synchronization signal block.
 18. Themethod according to claim 16, wherein the value of X is further relatedto a quantity of random access occasions comprised in one random accessconfiguration period P.
 19. The method according to claim 16, wherein avalue of the random access association period Y is 10 ms, 20 ms, 40 ms,80 ms, 160 ms, 320 ms, or 640 ms.
 20. The method according to claim 16,wherein any remaining random access occasions in the random accessassociation period Y are not used for accessing a network device. 21.The method according to claim 16, any remaining random access occasionsin the random access association period Y are not associated with anysynchronization signal block or any synchronization signal block group.22. The method according to claim 16, wherein a quantity of randomaccess occasions in one random access configuration period P is 1, 2, 4,or
 8. 23. The method according to claim 16, wherein the value of X or Yis related to: a quantity of actually transmitted synchronization signalblocks or synchronization signal block groups, a quantity ofsynchronization signal blocks or synchronization signal block groupsmapped to one random access occasion, and a quantity of random accessoccasions comprised in a random access configuration period P.
 24. Themethod according to claim 16, wherein a maximum quantity ofsynchronization signal blocks mapped to one random access occasion is 8or
 16. 25. The method according to claim 16, wherein when a quantity ofsynchronization signal blocks mapped to one random access occasion is N,and a quantity of contention-based or non-contention-based or all randomaccess preambles in one random access occasion is N1, a quantity N2 ofrandom access preambles mapped to one synchronization signal block is nomore than floor(N1/N) or N1/N, floor indicating rounding down to anearest integer; a value of N1 being any one or more values of 4, 8, 12,16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 128, or
 256. 26. Themethod according to claim 16, wherein the method further comprises:determining a granularity of a quantity of random access preambles basedon a quantity of synchronization signal blocks mapped to one randomaccess occasion, the random access preambles being used to access anetwork device.
 27. The method according to claim 16, wherein in onerandom access association period Y, synchronization signal blocks orsynchronization signal block groups are cyclically mapped to randomaccess occasions.
 28. The method according to claim 16, wherein indifferent random access association periods, a first random accessoccasion is mapped to a first synchronization signal block.
 29. Themethod according to claim 16, wherein the RACH configuration informationcomprises a physical random access channel configuration index (PRACH)configuration index and a random access preamble subcarrier spacing. 30.The method according to claim 29, wherein the PRACH configuration indexindicates one or more of: a preamble format, a random accessconfiguration period, a frame in which a random access resource islocated, a subframe index, or a start orthogonal frequency divisionmultiplexing (OFDM) symbol.
 31. The method according to claim 16,wherein the value of X is 1.